[BLOCK] Move all core block layer code to new block/ directory

drivers/block/ is right now a mix of core and driver parts. Lets move
the core parts to a new top level directory. Al will move the fs/
related block parts to block/ next.

Signed-off-by: Jens Axboe <axboe@suse.de>

12 files changed, 0 insertions, 11437 deletions

diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 51b0af1cebee..7b1cd93892be 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -409,16 +409,6 @@ config BLK_DEV_INITRD
 	  for details.
 
 
-#XXX - it makes sense to enable this only for 32-bit subarch's, not for x86_64
-#for instance.
-config LBD
-	bool "Support for Large Block Devices"
-	depends on X86 || (MIPS && 32BIT) || PPC32 || ARCH_S390_31 || SUPERH || UML
-	help
-	  Say Y here if you want to attach large (bigger than 2TB) discs to
-	  your machine, or if you want to have a raid or loopback device
-	  bigger than 2TB.  Otherwise say N.
-
 config CDROM_PKTCDVD
 	tristate "Packet writing on CD/DVD media"
 	depends on !UML
@@ -455,8 +445,6 @@ config CDROM_PKTCDVD_WCACHE
 
 source "drivers/s390/block/Kconfig"
 
-source "drivers/block/Kconfig.iosched"
-
 config ATA_OVER_ETH
 	tristate "ATA over Ethernet support"
 	depends on NET
diff --git a/drivers/block/Kconfig.iosched b/drivers/block/Kconfig.iosched
deleted file mode 100644
index 5b90d2fa63b8..000000000000
--- a/drivers/block/Kconfig.iosched
+++ /dev/null
@@ -1,69 +0,0 @@
-
-menu "IO Schedulers"
-
-config IOSCHED_NOOP
-	bool
-	default y
-	---help---
-	  The no-op I/O scheduler is a minimal scheduler that does basic merging
-	  and sorting. Its main uses include non-disk based block devices like
-	  memory devices, and specialised software or hardware environments
-	  that do their own scheduling and require only minimal assistance from
-	  the kernel.
-
-config IOSCHED_AS
-	tristate "Anticipatory I/O scheduler"
-	default y
-	---help---
-	  The anticipatory I/O scheduler is the default disk scheduler. It is
-	  generally a good choice for most environments, but is quite large and
-	  complex when compared to the deadline I/O scheduler, it can also be
-	  slower in some cases especially some database loads.
-
-config IOSCHED_DEADLINE
-	tristate "Deadline I/O scheduler"
-	default y
-	---help---
-	  The deadline I/O scheduler is simple and compact, and is often as
-	  good as the anticipatory I/O scheduler, and in some database
-	  workloads, better. In the case of a single process performing I/O to
-	  a disk at any one time, its behaviour is almost identical to the
-	  anticipatory I/O scheduler and so is a good choice.
-
-config IOSCHED_CFQ
-	tristate "CFQ I/O scheduler"
-	default y
-	---help---
-	  The CFQ I/O scheduler tries to distribute bandwidth equally
-	  among all processes in the system. It should provide a fair
-	  working environment, suitable for desktop systems.
-
-choice
-	prompt "Default I/O scheduler"
-	default DEFAULT_AS
-	help
-	  Select the I/O scheduler which will be used by default for all
-	  block devices.
-
-	config DEFAULT_AS
-		bool "Anticipatory" if IOSCHED_AS
-
-	config DEFAULT_DEADLINE
-		bool "Deadline" if IOSCHED_DEADLINE
-
-	config DEFAULT_CFQ
-		bool "CFQ" if IOSCHED_CFQ
-
-	config DEFAULT_NOOP
-		bool "No-op"
-
-endchoice
-
-config DEFAULT_IOSCHED
-	string
-	default "anticipatory" if DEFAULT_AS
-	default "deadline" if DEFAULT_DEADLINE
-	default "cfq" if DEFAULT_CFQ
-	default "noop" if DEFAULT_NOOP
-
-endmenu
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index 1cf09a1c065b..3ec1f8df87b1 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -4,21 +4,7 @@
 # 12 June 2000, Christoph Hellwig <hch@infradead.org>
 # Rewritten to use lists instead of if-statements.
 # 
-# Note : at this point, these files are compiled on all systems.
-# In the future, some of these should be built conditionally.
-#
-
-#
-# NOTE that ll_rw_blk.c must come early in linkage order - it starts the
-# kblockd threads
-#
-
-obj-y	:= elevator.o ll_rw_blk.o ioctl.o genhd.o scsi_ioctl.o
 
-obj-$(CONFIG_IOSCHED_NOOP)	+= noop-iosched.o
-obj-$(CONFIG_IOSCHED_AS)	+= as-iosched.o
-obj-$(CONFIG_IOSCHED_DEADLINE)	+= deadline-iosched.o
-obj-$(CONFIG_IOSCHED_CFQ)	+= cfq-iosched.o
 obj-$(CONFIG_MAC_FLOPPY)	+= swim3.o
 obj-$(CONFIG_BLK_DEV_FD)	+= floppy.o
 obj-$(CONFIG_BLK_DEV_FD98)	+= floppy98.o
diff --git a/drivers/block/as-iosched.c b/drivers/block/as-iosched.c
deleted file mode 100644
index c6744ff38294..000000000000
--- a/drivers/block/as-iosched.c
+++ /dev/null
@@ -1,1985 +0,0 @@
-/*
- *  linux/drivers/block/as-iosched.c
- *
- *  Anticipatory & deadline i/o scheduler.
- *
- *  Copyright (C) 2002 Jens Axboe <axboe@suse.de>
- *                     Nick Piggin <piggin@cyberone.com.au>
- *
- */
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/config.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/hash.h>
-#include <linux/rbtree.h>
-#include <linux/interrupt.h>
-
-#define REQ_SYNC	1
-#define REQ_ASYNC	0
-
-/*
- * See Documentation/block/as-iosched.txt
- */
-
-/*
- * max time before a read is submitted.
- */
-#define default_read_expire (HZ / 8)
-
-/*
- * ditto for writes, these limits are not hard, even
- * if the disk is capable of satisfying them.
- */
-#define default_write_expire (HZ / 4)
-
-/*
- * read_batch_expire describes how long we will allow a stream of reads to
- * persist before looking to see whether it is time to switch over to writes.
- */
-#define default_read_batch_expire (HZ / 2)
-
-/*
- * write_batch_expire describes how long we want a stream of writes to run for.
- * This is not a hard limit, but a target we set for the auto-tuning thingy.
- * See, the problem is: we can send a lot of writes to disk cache / TCQ in
- * a short amount of time...
- */
-#define default_write_batch_expire (HZ / 8)
-
-/*
- * max time we may wait to anticipate a read (default around 6ms)
- */
-#define default_antic_expire ((HZ / 150) ? HZ / 150 : 1)
-
-/*
- * Keep track of up to 20ms thinktimes. We can go as big as we like here,
- * however huge values tend to interfere and not decay fast enough. A program
- * might be in a non-io phase of operation. Waiting on user input for example,
- * or doing a lengthy computation. A small penalty can be justified there, and
- * will still catch out those processes that constantly have large thinktimes.
- */
-#define MAX_THINKTIME (HZ/50UL)
-
-/* Bits in as_io_context.state */
-enum as_io_states {
-	AS_TASK_RUNNING=0,	/* Process has not exitted */
-	AS_TASK_IOSTARTED,	/* Process has started some IO */
-	AS_TASK_IORUNNING,	/* Process has completed some IO */
-};
-
-enum anticipation_status {
-	ANTIC_OFF=0,		/* Not anticipating (normal operation)	*/
-	ANTIC_WAIT_REQ,		/* The last read has not yet completed  */
-	ANTIC_WAIT_NEXT,	/* Currently anticipating a request vs
-				   last read (which has completed) */
-	ANTIC_FINISHED,		/* Anticipating but have found a candidate
-				 * or timed out */
-};
-
-struct as_data {
-	/*
-	 * run time data
-	 */
-
-	struct request_queue *q;	/* the "owner" queue */
-
-	/*
-	 * requests (as_rq s) are present on both sort_list and fifo_list
-	 */
-	struct rb_root sort_list[2];
-	struct list_head fifo_list[2];
-
-	struct as_rq *next_arq[2];	/* next in sort order */
-	sector_t last_sector[2];	/* last REQ_SYNC & REQ_ASYNC sectors */
-	struct list_head *hash;		/* request hash */
-
-	unsigned long exit_prob;	/* probability a task will exit while
-					   being waited on */
-	unsigned long new_ttime_total; 	/* mean thinktime on new proc */
-	unsigned long new_ttime_mean;
-	u64 new_seek_total;		/* mean seek on new proc */
-	sector_t new_seek_mean;
-
-	unsigned long current_batch_expires;
-	unsigned long last_check_fifo[2];
-	int changed_batch;		/* 1: waiting for old batch to end */
-	int new_batch;			/* 1: waiting on first read complete */
-	int batch_data_dir;		/* current batch REQ_SYNC / REQ_ASYNC */
-	int write_batch_count;		/* max # of reqs in a write batch */
-	int current_write_count;	/* how many requests left this batch */
-	int write_batch_idled;		/* has the write batch gone idle? */
-	mempool_t *arq_pool;
-
-	enum anticipation_status antic_status;
-	unsigned long antic_start;	/* jiffies: when it started */
-	struct timer_list antic_timer;	/* anticipatory scheduling timer */
-	struct work_struct antic_work;	/* Deferred unplugging */
-	struct io_context *io_context;	/* Identify the expected process */
-	int ioc_finished; /* IO associated with io_context is finished */
-	int nr_dispatched;
-
-	/*
-	 * settings that change how the i/o scheduler behaves
-	 */
-	unsigned long fifo_expire[2];
-	unsigned long batch_expire[2];
-	unsigned long antic_expire;
-};
-
-#define list_entry_fifo(ptr)	list_entry((ptr), struct as_rq, fifo)
-
-/*
- * per-request data.
- */
-enum arq_state {
-	AS_RQ_NEW=0,		/* New - not referenced and not on any lists */
-	AS_RQ_QUEUED,		/* In the request queue. It belongs to the
-				   scheduler */
-	AS_RQ_DISPATCHED,	/* On the dispatch list. It belongs to the
-				   driver now */
-	AS_RQ_PRESCHED,		/* Debug poisoning for requests being used */
-	AS_RQ_REMOVED,
-	AS_RQ_MERGED,
-	AS_RQ_POSTSCHED,	/* when they shouldn't be */
-};
-
-struct as_rq {
-	/*
-	 * rbtree index, key is the starting offset
-	 */
-	struct rb_node rb_node;
-	sector_t rb_key;
-
-	struct request *request;
-
-	struct io_context *io_context;	/* The submitting task */
-
-	/*
-	 * request hash, key is the ending offset (for back merge lookup)
-	 */
-	struct list_head hash;
-	unsigned int on_hash;
-
-	/*
-	 * expire fifo
-	 */
-	struct list_head fifo;
-	unsigned long expires;
-
-	unsigned int is_sync;
-	enum arq_state state;
-};
-
-#define RQ_DATA(rq)	((struct as_rq *) (rq)->elevator_private)
-
-static kmem_cache_t *arq_pool;
-
-/*
- * IO Context helper functions
- */
-
-/* Called to deallocate the as_io_context */
-static void free_as_io_context(struct as_io_context *aic)
-{
-	kfree(aic);
-}
-
-/* Called when the task exits */
-static void exit_as_io_context(struct as_io_context *aic)
-{
-	WARN_ON(!test_bit(AS_TASK_RUNNING, &aic->state));
-	clear_bit(AS_TASK_RUNNING, &aic->state);
-}
-
-static struct as_io_context *alloc_as_io_context(void)
-{
-	struct as_io_context *ret;
-
-	ret = kmalloc(sizeof(*ret), GFP_ATOMIC);
-	if (ret) {
-		ret->dtor = free_as_io_context;
-		ret->exit = exit_as_io_context;
-		ret->state = 1 << AS_TASK_RUNNING;
-		atomic_set(&ret->nr_queued, 0);
-		atomic_set(&ret->nr_dispatched, 0);
-		spin_lock_init(&ret->lock);
-		ret->ttime_total = 0;
-		ret->ttime_samples = 0;
-		ret->ttime_mean = 0;
-		ret->seek_total = 0;
-		ret->seek_samples = 0;
-		ret->seek_mean = 0;
-	}
-
-	return ret;
-}
-
-/*
- * If the current task has no AS IO context then create one and initialise it.
- * Then take a ref on the task's io context and return it.
- */
-static struct io_context *as_get_io_context(void)
-{
-	struct io_context *ioc = get_io_context(GFP_ATOMIC);
-	if (ioc && !ioc->aic) {
-		ioc->aic = alloc_as_io_context();
-		if (!ioc->aic) {
-			put_io_context(ioc);
-			ioc = NULL;
-		}
-	}
-	return ioc;
-}
-
-static void as_put_io_context(struct as_rq *arq)
-{
-	struct as_io_context *aic;
-
-	if (unlikely(!arq->io_context))
-		return;
-
-	aic = arq->io_context->aic;
-
-	if (arq->is_sync == REQ_SYNC && aic) {
-		spin_lock(&aic->lock);
-		set_bit(AS_TASK_IORUNNING, &aic->state);
-		aic->last_end_request = jiffies;
-		spin_unlock(&aic->lock);
-	}
-
-	put_io_context(arq->io_context);
-}
-
-/*
- * the back merge hash support functions
- */
-static const int as_hash_shift = 6;
-#define AS_HASH_BLOCK(sec)	((sec) >> 3)
-#define AS_HASH_FN(sec)		(hash_long(AS_HASH_BLOCK((sec)), as_hash_shift))
-#define AS_HASH_ENTRIES		(1 << as_hash_shift)
-#define rq_hash_key(rq)		((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr)	list_entry((ptr), struct as_rq, hash)
-
-static inline void __as_del_arq_hash(struct as_rq *arq)
-{
-	arq->on_hash = 0;
-	list_del_init(&arq->hash);
-}
-
-static inline void as_del_arq_hash(struct as_rq *arq)
-{
-	if (arq->on_hash)
-		__as_del_arq_hash(arq);
-}
-
-static void as_add_arq_hash(struct as_data *ad, struct as_rq *arq)
-{
-	struct request *rq = arq->request;
-
-	BUG_ON(arq->on_hash);
-
-	arq->on_hash = 1;
-	list_add(&arq->hash, &ad->hash[AS_HASH_FN(rq_hash_key(rq))]);
-}
-
-/*
- * move hot entry to front of chain
- */
-static inline void as_hot_arq_hash(struct as_data *ad, struct as_rq *arq)
-{
-	struct request *rq = arq->request;
-	struct list_head *head = &ad->hash[AS_HASH_FN(rq_hash_key(rq))];
-
-	if (!arq->on_hash) {
-		WARN_ON(1);
-		return;
-	}
-
-	if (arq->hash.prev != head) {
-		list_del(&arq->hash);
-		list_add(&arq->hash, head);
-	}
-}
-
-static struct request *as_find_arq_hash(struct as_data *ad, sector_t offset)
-{
-	struct list_head *hash_list = &ad->hash[AS_HASH_FN(offset)];
-	struct list_head *entry, *next = hash_list->next;
-
-	while ((entry = next) != hash_list) {
-		struct as_rq *arq = list_entry_hash(entry);
-		struct request *__rq = arq->request;
-
-		next = entry->next;
-
-		BUG_ON(!arq->on_hash);
-
-		if (!rq_mergeable(__rq)) {
-			as_del_arq_hash(arq);
-			continue;
-		}
-
-		if (rq_hash_key(__rq) == offset)
-			return __rq;
-	}
-
-	return NULL;
-}
-
-/*
- * rb tree support functions
- */
-#define RB_NONE		(2)
-#define RB_EMPTY(root)	((root)->rb_node == NULL)
-#define ON_RB(node)	((node)->rb_color != RB_NONE)
-#define RB_CLEAR(node)	((node)->rb_color = RB_NONE)
-#define rb_entry_arq(node)	rb_entry((node), struct as_rq, rb_node)
-#define ARQ_RB_ROOT(ad, arq)	(&(ad)->sort_list[(arq)->is_sync])
-#define rq_rb_key(rq)		(rq)->sector
-
-/*
- * as_find_first_arq finds the first (lowest sector numbered) request
- * for the specified data_dir. Used to sweep back to the start of the disk
- * (1-way elevator) after we process the last (highest sector) request.
- */
-static struct as_rq *as_find_first_arq(struct as_data *ad, int data_dir)
-{
-	struct rb_node *n = ad->sort_list[data_dir].rb_node;
-
-	if (n == NULL)
-		return NULL;
-
-	for (;;) {
-		if (n->rb_left == NULL)
-			return rb_entry_arq(n);
-
-		n = n->rb_left;
-	}
-}
-
-/*
- * Add the request to the rb tree if it is unique.  If there is an alias (an
- * existing request against the same sector), which can happen when using
- * direct IO, then return the alias.
- */
-static struct as_rq *as_add_arq_rb(struct as_data *ad, struct as_rq *arq)
-{
-	struct rb_node **p = &ARQ_RB_ROOT(ad, arq)->rb_node;
-	struct rb_node *parent = NULL;
-	struct as_rq *__arq;
-	struct request *rq = arq->request;
-
-	arq->rb_key = rq_rb_key(rq);
-
-	while (*p) {
-		parent = *p;
-		__arq = rb_entry_arq(parent);
-
-		if (arq->rb_key < __arq->rb_key)
-			p = &(*p)->rb_left;
-		else if (arq->rb_key > __arq->rb_key)
-			p = &(*p)->rb_right;
-		else
-			return __arq;
-	}
-
-	rb_link_node(&arq->rb_node, parent, p);
-	rb_insert_color(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
-
-	return NULL;
-}
-
-static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq)
-{
-	if (!ON_RB(&arq->rb_node)) {
-		WARN_ON(1);
-		return;
-	}
-
-	rb_erase(&arq->rb_node, ARQ_RB_ROOT(ad, arq));
-	RB_CLEAR(&arq->rb_node);
-}
-
-static struct request *
-as_find_arq_rb(struct as_data *ad, sector_t sector, int data_dir)
-{
-	struct rb_node *n = ad->sort_list[data_dir].rb_node;
-	struct as_rq *arq;
-
-	while (n) {
-		arq = rb_entry_arq(n);
-
-		if (sector < arq->rb_key)
-			n = n->rb_left;
-		else if (sector > arq->rb_key)
-			n = n->rb_right;
-		else
-			return arq->request;
-	}
-
-	return NULL;
-}
-
-/*
- * IO Scheduler proper
- */
-
-#define MAXBACK (1024 * 1024)	/*
-				 * Maximum distance the disk will go backward
-				 * for a request.
-				 */
-
-#define BACK_PENALTY	2
-
-/*
- * as_choose_req selects the preferred one of two requests of the same data_dir
- * ignoring time - eg. timeouts, which is the job of as_dispatch_request
- */
-static struct as_rq *
-as_choose_req(struct as_data *ad, struct as_rq *arq1, struct as_rq *arq2)
-{
-	int data_dir;
-	sector_t last, s1, s2, d1, d2;
-	int r1_wrap=0, r2_wrap=0;	/* requests are behind the disk head */
-	const sector_t maxback = MAXBACK;
-
-	if (arq1 == NULL || arq1 == arq2)
-		return arq2;
-	if (arq2 == NULL)
-		return arq1;
-
-	data_dir = arq1->is_sync;
-
-	last = ad->last_sector[data_dir];
-	s1 = arq1->request->sector;
-	s2 = arq2->request->sector;
-
-	BUG_ON(data_dir != arq2->is_sync);
-
-	/*
-	 * Strict one way elevator _except_ in the case where we allow
-	 * short backward seeks which are biased as twice the cost of a
-	 * similar forward seek.
-	 */
-	if (s1 >= last)
-		d1 = s1 - last;
-	else if (s1+maxback >= last)
-		d1 = (last - s1)*BACK_PENALTY;
-	else {
-		r1_wrap = 1;
-		d1 = 0; /* shut up, gcc */
-	}
-
-	if (s2 >= last)
-		d2 = s2 - last;
-	else if (s2+maxback >= last)
-		d2 = (last - s2)*BACK_PENALTY;
-	else {
-		r2_wrap = 1;
-		d2 = 0;
-	}
-
-	/* Found required data */
-	if (!r1_wrap && r2_wrap)
-		return arq1;
-	else if (!r2_wrap && r1_wrap)
-		return arq2;
-	else if (r1_wrap && r2_wrap) {
-		/* both behind the head */
-		if (s1 <= s2)
-			return arq1;
-		else
-			return arq2;
-	}
-
-	/* Both requests in front of the head */
-	if (d1 < d2)
-		return arq1;
-	else if (d2 < d1)
-		return arq2;
-	else {
-		if (s1 >= s2)
-			return arq1;
-		else
-			return arq2;
-	}
-}
-
-/*
- * as_find_next_arq finds the next request after @prev in elevator order.
- * this with as_choose_req form the basis for how the scheduler chooses
- * what request to process next. Anticipation works on top of this.
- */
-static struct as_rq *as_find_next_arq(struct as_data *ad, struct as_rq *last)
-{
-	const int data_dir = last->is_sync;
-	struct as_rq *ret;
-	struct rb_node *rbnext = rb_next(&last->rb_node);
-	struct rb_node *rbprev = rb_prev(&last->rb_node);
-	struct as_rq *arq_next, *arq_prev;
-
-	BUG_ON(!ON_RB(&last->rb_node));
-
-	if (rbprev)
-		arq_prev = rb_entry_arq(rbprev);
-	else
-		arq_prev = NULL;
-
-	if (rbnext)
-		arq_next = rb_entry_arq(rbnext);
-	else {
-		arq_next = as_find_first_arq(ad, data_dir);
-		if (arq_next == last)
-			arq_next = NULL;
-	}
-
-	ret = as_choose_req(ad,	arq_next, arq_prev);
-
-	return ret;
-}
-
-/*
- * anticipatory scheduling functions follow
- */
-
-/*
- * as_antic_expired tells us when we have anticipated too long.
- * The funny "absolute difference" math on the elapsed time is to handle
- * jiffy wraps, and disks which have been idle for 0x80000000 jiffies.
- */
-static int as_antic_expired(struct as_data *ad)
-{
-	long delta_jif;
-
-	delta_jif = jiffies - ad->antic_start;
-	if (unlikely(delta_jif < 0))
-		delta_jif = -delta_jif;
-	if (delta_jif < ad->antic_expire)
-		return 0;
-
-	return 1;
-}
-
-/*
- * as_antic_waitnext starts anticipating that a nice request will soon be
- * submitted. See also as_antic_waitreq
- */
-static void as_antic_waitnext(struct as_data *ad)
-{
-	unsigned long timeout;
-
-	BUG_ON(ad->antic_status != ANTIC_OFF
-			&& ad->antic_status != ANTIC_WAIT_REQ);
-
-	timeout = ad->antic_start + ad->antic_expire;
-
-	mod_timer(&ad->antic_timer, timeout);
-
-	ad->antic_status = ANTIC_WAIT_NEXT;
-}
-
-/*
- * as_antic_waitreq starts anticipating. We don't start timing the anticipation
- * until the request that we're anticipating on has finished. This means we
- * are timing from when the candidate process wakes up hopefully.
- */
-static void as_antic_waitreq(struct as_data *ad)
-{
-	BUG_ON(ad->antic_status == ANTIC_FINISHED);
-	if (ad->antic_status == ANTIC_OFF) {
-		if (!ad->io_context || ad->ioc_finished)
-			as_antic_waitnext(ad);
-		else
-			ad->antic_status = ANTIC_WAIT_REQ;
-	}
-}
-
-/*
- * This is called directly by the functions in this file to stop anticipation.
- * We kill the timer and schedule a call to the request_fn asap.
- */
-static void as_antic_stop(struct as_data *ad)
-{
-	int status = ad->antic_status;
-
-	if (status == ANTIC_WAIT_REQ || status == ANTIC_WAIT_NEXT) {
-		if (status == ANTIC_WAIT_NEXT)
-			del_timer(&ad->antic_timer);
-		ad->antic_status = ANTIC_FINISHED;
-		/* see as_work_handler */
-		kblockd_schedule_work(&ad->antic_work);
-	}
-}
-
-/*
- * as_antic_timeout is the timer function set by as_antic_waitnext.
- */
-static void as_antic_timeout(unsigned long data)
-{
-	struct request_queue *q = (struct request_queue *)data;
-	struct as_data *ad = q->elevator->elevator_data;
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	if (ad->antic_status == ANTIC_WAIT_REQ
-			|| ad->antic_status == ANTIC_WAIT_NEXT) {
-		struct as_io_context *aic = ad->io_context->aic;
-
-		ad->antic_status = ANTIC_FINISHED;
-		kblockd_schedule_work(&ad->antic_work);
-
-		if (aic->ttime_samples == 0) {
-			/* process anticipated on has exitted or timed out*/
-			ad->exit_prob = (7*ad->exit_prob + 256)/8;
-		}
-	}
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-/*
- * as_close_req decides if one request is considered "close" to the
- * previous one issued.
- */
-static int as_close_req(struct as_data *ad, struct as_rq *arq)
-{
-	unsigned long delay;	/* milliseconds */
-	sector_t last = ad->last_sector[ad->batch_data_dir];
-	sector_t next = arq->request->sector;
-	sector_t delta; /* acceptable close offset (in sectors) */
-
-	if (ad->antic_status == ANTIC_OFF || !ad->ioc_finished)
-		delay = 0;
-	else
-		delay = ((jiffies - ad->antic_start) * 1000) / HZ;
-
-	if (delay <= 1)
-		delta = 64;
-	else if (delay <= 20 && delay <= ad->antic_expire)
-		delta = 64 << (delay-1);
-	else
-		return 1;
-
-	return (last - (delta>>1) <= next) && (next <= last + delta);
-}
-
-/*
- * as_can_break_anticipation returns true if we have been anticipating this
- * request.
- *
- * It also returns true if the process against which we are anticipating
- * submits a write - that's presumably an fsync, O_SYNC write, etc. We want to
- * dispatch it ASAP, because we know that application will not be submitting
- * any new reads.
- *
- * If the task which has submitted the request has exitted, break anticipation.
- *
- * If this task has queued some other IO, do not enter enticipation.
- */
-static int as_can_break_anticipation(struct as_data *ad, struct as_rq *arq)
-{
-	struct io_context *ioc;
-	struct as_io_context *aic;
-	sector_t s;
-
-	ioc = ad->io_context;
-	BUG_ON(!ioc);
-
-	if (arq && ioc == arq->io_context) {
-		/* request from same process */
-		return 1;
-	}
-
-	if (ad->ioc_finished && as_antic_expired(ad)) {
-		/*
-		 * In this situation status should really be FINISHED,
-		 * however the timer hasn't had the chance to run yet.
-		 */
-		return 1;
-	}
-
-	aic = ioc->aic;
-	if (!aic)
-		return 0;
-
-	if (!test_bit(AS_TASK_RUNNING, &aic->state)) {
-		/* process anticipated on has exitted */
-		if (aic->ttime_samples == 0)
-			ad->exit_prob = (7*ad->exit_prob + 256)/8;
-		return 1;
-	}
-
-	if (atomic_read(&aic->nr_queued) > 0) {
-		/* process has more requests queued */
-		return 1;
-	}
-
-	if (atomic_read(&aic->nr_dispatched) > 0) {
-		/* process has more requests dispatched */
-		return 1;
-	}
-
-	if (arq && arq->is_sync == REQ_SYNC && as_close_req(ad, arq)) {
-		/*
-		 * Found a close request that is not one of ours.
-		 *
-		 * This makes close requests from another process reset
-		 * our thinktime delay. Is generally useful when there are
-		 * two or more cooperating processes working in the same
-		 * area.
-		 */
-		spin_lock(&aic->lock);
-		aic->last_end_request = jiffies;
-		spin_unlock(&aic->lock);
-		return 1;
-	}
-
-
-	if (aic->ttime_samples == 0) {
-		if (ad->new_ttime_mean > ad->antic_expire)
-			return 1;
-		if (ad->exit_prob > 128)
-			return 1;
-	} else if (aic->ttime_mean > ad->antic_expire) {
-		/* the process thinks too much between requests */
-		return 1;
-	}
-
-	if (!arq)
-		return 0;
-
-	if (ad->last_sector[REQ_SYNC] < arq->request->sector)
-		s = arq->request->sector - ad->last_sector[REQ_SYNC];
-	else
-		s = ad->last_sector[REQ_SYNC] - arq->request->sector;
-
-	if (aic->seek_samples == 0) {
-		/*
-		 * Process has just started IO. Use past statistics to
-		 * guage success possibility
-		 */
-		if (ad->new_seek_mean > s) {
-			/* this request is better than what we're expecting */
-			return 1;
-		}
-
-	} else {
-		if (aic->seek_mean > s) {
-			/* this request is better than what we're expecting */
-			return 1;
-		}
-	}
-
-	return 0;
-}
-
-/*
- * as_can_anticipate indicates weather we should either run arq
- * or keep anticipating a better request.
- */
-static int as_can_anticipate(struct as_data *ad, struct as_rq *arq)
-{
-	if (!ad->io_context)
-		/*
-		 * Last request submitted was a write
-		 */
-		return 0;
-
-	if (ad->antic_status == ANTIC_FINISHED)
-		/*
-		 * Don't restart if we have just finished. Run the next request
-		 */
-		return 0;
-
-	if (as_can_break_anticipation(ad, arq))
-		/*
-		 * This request is a good candidate. Don't keep anticipating,
-		 * run it.
-		 */
-		return 0;
-
-	/*
-	 * OK from here, we haven't finished, and don't have a decent request!
-	 * Status is either ANTIC_OFF so start waiting,
-	 * ANTIC_WAIT_REQ so continue waiting for request to finish
-	 * or ANTIC_WAIT_NEXT so continue waiting for an acceptable request.
-	 *
-	 */
-
-	return 1;
-}
-
-static void as_update_thinktime(struct as_data *ad, struct as_io_context *aic, unsigned long ttime)
-{
-	/* fixed point: 1.0 == 1<<8 */
-	if (aic->ttime_samples == 0) {
-		ad->new_ttime_total = (7*ad->new_ttime_total + 256*ttime) / 8;
-		ad->new_ttime_mean = ad->new_ttime_total / 256;
-
-		ad->exit_prob = (7*ad->exit_prob)/8;
-	}
-	aic->ttime_samples = (7*aic->ttime_samples + 256) / 8;
-	aic->ttime_total = (7*aic->ttime_total + 256*ttime) / 8;
-	aic->ttime_mean = (aic->ttime_total + 128) / aic->ttime_samples;
-}
-
-static void as_update_seekdist(struct as_data *ad, struct as_io_context *aic, sector_t sdist)
-{
-	u64 total;
-
-	if (aic->seek_samples == 0) {
-		ad->new_seek_total = (7*ad->new_seek_total + 256*(u64)sdist)/8;
-		ad->new_seek_mean = ad->new_seek_total / 256;
-	}
-
-	/*
-	 * Don't allow the seek distance to get too large from the
-	 * odd fragment, pagein, etc
-	 */
-	if (aic->seek_samples <= 60) /* second&third seek */
-		sdist = min(sdist, (aic->seek_mean * 4) + 2*1024*1024);
-	else
-		sdist = min(sdist, (aic->seek_mean * 4)	+ 2*1024*64);
-
-	aic->seek_samples = (7*aic->seek_samples + 256) / 8;
-	aic->seek_total = (7*aic->seek_total + (u64)256*sdist) / 8;
-	total = aic->seek_total + (aic->seek_samples/2);
-	do_div(total, aic->seek_samples);
-	aic->seek_mean = (sector_t)total;
-}
-
-/*
- * as_update_iohist keeps a decaying histogram of IO thinktimes, and
- * updates @aic->ttime_mean based on that. It is called when a new
- * request is queued.
- */
-static void as_update_iohist(struct as_data *ad, struct as_io_context *aic, struct request *rq)
-{
-	struct as_rq *arq = RQ_DATA(rq);
-	int data_dir = arq->is_sync;
-	unsigned long thinktime;
-	sector_t seek_dist;
-
-	if (aic == NULL)
-		return;
-
-	if (data_dir == REQ_SYNC) {
-		unsigned long in_flight = atomic_read(&aic->nr_queued)
-					+ atomic_read(&aic->nr_dispatched);
-		spin_lock(&aic->lock);
-		if (test_bit(AS_TASK_IORUNNING, &aic->state) ||
-			test_bit(AS_TASK_IOSTARTED, &aic->state)) {
-			/* Calculate read -> read thinktime */
-			if (test_bit(AS_TASK_IORUNNING, &aic->state)
-							&& in_flight == 0) {
-				thinktime = jiffies - aic->last_end_request;
-				thinktime = min(thinktime, MAX_THINKTIME-1);
-			} else
-				thinktime = 0;
-			as_update_thinktime(ad, aic, thinktime);
-
-			/* Calculate read -> read seek distance */
-			if (aic->last_request_pos < rq->sector)
-				seek_dist = rq->sector - aic->last_request_pos;
-			else
-				seek_dist = aic->last_request_pos - rq->sector;
-			as_update_seekdist(ad, aic, seek_dist);
-		}
-		aic->last_request_pos = rq->sector + rq->nr_sectors;
-		set_bit(AS_TASK_IOSTARTED, &aic->state);
-		spin_unlock(&aic->lock);
-	}
-}
-
-/*
- * as_update_arq must be called whenever a request (arq) is added to
- * the sort_list. This function keeps caches up to date, and checks if the
- * request might be one we are "anticipating"
- */
-static void as_update_arq(struct as_data *ad, struct as_rq *arq)
-{
-	const int data_dir = arq->is_sync;
-
-	/* keep the next_arq cache up to date */
-	ad->next_arq[data_dir] = as_choose_req(ad, arq, ad->next_arq[data_dir]);
-
-	/*
-	 * have we been anticipating this request?
-	 * or does it come from the same process as the one we are anticipating
-	 * for?
-	 */
-	if (ad->antic_status == ANTIC_WAIT_REQ
-			|| ad->antic_status == ANTIC_WAIT_NEXT) {
-		if (as_can_break_anticipation(ad, arq))
-			as_antic_stop(ad);
-	}
-}
-
-/*
- * Gathers timings and resizes the write batch automatically
- */
-static void update_write_batch(struct as_data *ad)
-{
-	unsigned long batch = ad->batch_expire[REQ_ASYNC];
-	long write_time;
-
-	write_time = (jiffies - ad->current_batch_expires) + batch;
-	if (write_time < 0)
-		write_time = 0;
-
-	if (write_time > batch && !ad->write_batch_idled) {
-		if (write_time > batch * 3)
-			ad->write_batch_count /= 2;
-		else
-			ad->write_batch_count--;
-	} else if (write_time < batch && ad->current_write_count == 0) {
-		if (batch > write_time * 3)
-			ad->write_batch_count *= 2;
-		else
-			ad->write_batch_count++;
-	}
-
-	if (ad->write_batch_count < 1)
-		ad->write_batch_count = 1;
-}
-
-/*
- * as_completed_request is to be called when a request has completed and
- * returned something to the requesting process, be it an error or data.
- */
-static void as_completed_request(request_queue_t *q, struct request *rq)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	struct as_rq *arq = RQ_DATA(rq);
-
-	WARN_ON(!list_empty(&rq->queuelist));
-
-	if (arq->state != AS_RQ_REMOVED) {
-		printk("arq->state %d\n", arq->state);
-		WARN_ON(1);
-		goto out;
-	}
-
-	if (ad->changed_batch && ad->nr_dispatched == 1) {
-		kblockd_schedule_work(&ad->antic_work);
-		ad->changed_batch = 0;
-
-		if (ad->batch_data_dir == REQ_SYNC)
-			ad->new_batch = 1;
-	}
-	WARN_ON(ad->nr_dispatched == 0);
-	ad->nr_dispatched--;
-
-	/*
-	 * Start counting the batch from when a request of that direction is
-	 * actually serviced. This should help devices with big TCQ windows
-	 * and writeback caches
-	 */
-	if (ad->new_batch && ad->batch_data_dir == arq->is_sync) {
-		update_write_batch(ad);
-		ad->current_batch_expires = jiffies +
-				ad->batch_expire[REQ_SYNC];
-		ad->new_batch = 0;
-	}
-
-	if (ad->io_context == arq->io_context && ad->io_context) {
-		ad->antic_start = jiffies;
-		ad->ioc_finished = 1;
-		if (ad->antic_status == ANTIC_WAIT_REQ) {
-			/*
-			 * We were waiting on this request, now anticipate
-			 * the next one
-			 */
-			as_antic_waitnext(ad);
-		}
-	}
-
-	as_put_io_context(arq);
-out:
-	arq->state = AS_RQ_POSTSCHED;
-}
-
-/*
- * as_remove_queued_request removes a request from the pre dispatch queue
- * without updating refcounts. It is expected the caller will drop the
- * reference unless it replaces the request at somepart of the elevator
- * (ie. the dispatch queue)
- */
-static void as_remove_queued_request(request_queue_t *q, struct request *rq)
-{
-	struct as_rq *arq = RQ_DATA(rq);
-	const int data_dir = arq->is_sync;
-	struct as_data *ad = q->elevator->elevator_data;
-
-	WARN_ON(arq->state != AS_RQ_QUEUED);
-
-	if (arq->io_context && arq->io_context->aic) {
-		BUG_ON(!atomic_read(&arq->io_context->aic->nr_queued));
-		atomic_dec(&arq->io_context->aic->nr_queued);
-	}
-
-	/*
-	 * Update the "next_arq" cache if we are about to remove its
-	 * entry
-	 */
-	if (ad->next_arq[data_dir] == arq)
-		ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
-
-	list_del_init(&arq->fifo);
-	as_del_arq_hash(arq);
-	as_del_arq_rb(ad, arq);
-}
-
-/*
- * as_fifo_expired returns 0 if there are no expired reads on the fifo,
- * 1 otherwise.  It is ratelimited so that we only perform the check once per
- * `fifo_expire' interval.  Otherwise a large number of expired requests
- * would create a hopeless seekstorm.
- *
- * See as_antic_expired comment.
- */
-static int as_fifo_expired(struct as_data *ad, int adir)
-{
-	struct as_rq *arq;
-	long delta_jif;
-
-	delta_jif = jiffies - ad->last_check_fifo[adir];
-	if (unlikely(delta_jif < 0))
-		delta_jif = -delta_jif;
-	if (delta_jif < ad->fifo_expire[adir])
-		return 0;
-
-	ad->last_check_fifo[adir] = jiffies;
-
-	if (list_empty(&ad->fifo_list[adir]))
-		return 0;
-
-	arq = list_entry_fifo(ad->fifo_list[adir].next);
-
-	return time_after(jiffies, arq->expires);
-}
-
-/*
- * as_batch_expired returns true if the current batch has expired. A batch
- * is a set of reads or a set of writes.
- */
-static inline int as_batch_expired(struct as_data *ad)
-{
-	if (ad->changed_batch || ad->new_batch)
-		return 0;
-
-	if (ad->batch_data_dir == REQ_SYNC)
-		/* TODO! add a check so a complete fifo gets written? */
-		return time_after(jiffies, ad->current_batch_expires);
-
-	return time_after(jiffies, ad->current_batch_expires)
-		|| ad->current_write_count == 0;
-}
-
-/*
- * move an entry to dispatch queue
- */
-static void as_move_to_dispatch(struct as_data *ad, struct as_rq *arq)
-{
-	struct request *rq = arq->request;
-	const int data_dir = arq->is_sync;
-
-	BUG_ON(!ON_RB(&arq->rb_node));
-
-	as_antic_stop(ad);
-	ad->antic_status = ANTIC_OFF;
-
-	/*
-	 * This has to be set in order to be correctly updated by
-	 * as_find_next_arq
-	 */
-	ad->last_sector[data_dir] = rq->sector + rq->nr_sectors;
-
-	if (data_dir == REQ_SYNC) {
-		/* In case we have to anticipate after this */
-		copy_io_context(&ad->io_context, &arq->io_context);
-	} else {
-		if (ad->io_context) {
-			put_io_context(ad->io_context);
-			ad->io_context = NULL;
-		}
-
-		if (ad->current_write_count != 0)
-			ad->current_write_count--;
-	}
-	ad->ioc_finished = 0;
-
-	ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
-
-	/*
-	 * take it off the sort and fifo list, add to dispatch queue
-	 */
-	while (!list_empty(&rq->queuelist)) {
-		struct request *__rq = list_entry_rq(rq->queuelist.next);
-		struct as_rq *__arq = RQ_DATA(__rq);
-
-		list_del(&__rq->queuelist);
-
-		elv_dispatch_add_tail(ad->q, __rq);
-
-		if (__arq->io_context && __arq->io_context->aic)
-			atomic_inc(&__arq->io_context->aic->nr_dispatched);
-
-		WARN_ON(__arq->state != AS_RQ_QUEUED);
-		__arq->state = AS_RQ_DISPATCHED;
-
-		ad->nr_dispatched++;
-	}
-
-	as_remove_queued_request(ad->q, rq);
-	WARN_ON(arq->state != AS_RQ_QUEUED);
-
-	elv_dispatch_sort(ad->q, rq);
-
-	arq->state = AS_RQ_DISPATCHED;
-	if (arq->io_context && arq->io_context->aic)
-		atomic_inc(&arq->io_context->aic->nr_dispatched);
-	ad->nr_dispatched++;
-}
-
-/*
- * as_dispatch_request selects the best request according to
- * read/write expire, batch expire, etc, and moves it to the dispatch
- * queue. Returns 1 if a request was found, 0 otherwise.
- */
-static int as_dispatch_request(request_queue_t *q, int force)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	struct as_rq *arq;
-	const int reads = !list_empty(&ad->fifo_list[REQ_SYNC]);
-	const int writes = !list_empty(&ad->fifo_list[REQ_ASYNC]);
-
-	if (unlikely(force)) {
-		/*
-		 * Forced dispatch, accounting is useless.  Reset
-		 * accounting states and dump fifo_lists.  Note that
-		 * batch_data_dir is reset to REQ_SYNC to avoid
-		 * screwing write batch accounting as write batch
-		 * accounting occurs on W->R transition.
-		 */
-		int dispatched = 0;
-
-		ad->batch_data_dir = REQ_SYNC;
-		ad->changed_batch = 0;
-		ad->new_batch = 0;
-
-		while (ad->next_arq[REQ_SYNC]) {
-			as_move_to_dispatch(ad, ad->next_arq[REQ_SYNC]);
-			dispatched++;
-		}
-		ad->last_check_fifo[REQ_SYNC] = jiffies;
-
-		while (ad->next_arq[REQ_ASYNC]) {
-			as_move_to_dispatch(ad, ad->next_arq[REQ_ASYNC]);
-			dispatched++;
-		}
-		ad->last_check_fifo[REQ_ASYNC] = jiffies;
-
-		return dispatched;
-	}
-
-	/* Signal that the write batch was uncontended, so we can't time it */
-	if (ad->batch_data_dir == REQ_ASYNC && !reads) {
-		if (ad->current_write_count == 0 || !writes)
-			ad->write_batch_idled = 1;
-	}
-
-	if (!(reads || writes)
-		|| ad->antic_status == ANTIC_WAIT_REQ
-		|| ad->antic_status == ANTIC_WAIT_NEXT
-		|| ad->changed_batch)
-		return 0;
-
-	if (!(reads && writes && as_batch_expired(ad)) ) {
-		/*
-		 * batch is still running or no reads or no writes
-		 */
-		arq = ad->next_arq[ad->batch_data_dir];
-
-		if (ad->batch_data_dir == REQ_SYNC && ad->antic_expire) {
-			if (as_fifo_expired(ad, REQ_SYNC))
-				goto fifo_expired;
-
-			if (as_can_anticipate(ad, arq)) {
-				as_antic_waitreq(ad);
-				return 0;
-			}
-		}
-
-		if (arq) {
-			/* we have a "next request" */
-			if (reads && !writes)
-				ad->current_batch_expires =
-					jiffies + ad->batch_expire[REQ_SYNC];
-			goto dispatch_request;
-		}
-	}
-
-	/*
-	 * at this point we are not running a batch. select the appropriate
-	 * data direction (read / write)
-	 */
-
-	if (reads) {
-		BUG_ON(RB_EMPTY(&ad->sort_list[REQ_SYNC]));
-
-		if (writes && ad->batch_data_dir == REQ_SYNC)
-			/*
-			 * Last batch was a read, switch to writes
-			 */
-			goto dispatch_writes;
-
-		if (ad->batch_data_dir == REQ_ASYNC) {
-			WARN_ON(ad->new_batch);
-			ad->changed_batch = 1;
-		}
-		ad->batch_data_dir = REQ_SYNC;
-		arq = list_entry_fifo(ad->fifo_list[ad->batch_data_dir].next);
-		ad->last_check_fifo[ad->batch_data_dir] = jiffies;
-		goto dispatch_request;
-	}
-
-	/*
-	 * the last batch was a read
-	 */
-
-	if (writes) {
-dispatch_writes:
-		BUG_ON(RB_EMPTY(&ad->sort_list[REQ_ASYNC]));
-
-		if (ad->batch_data_dir == REQ_SYNC) {
-			ad->changed_batch = 1;
-
-			/*
-			 * new_batch might be 1 when the queue runs out of
-			 * reads. A subsequent submission of a write might
-			 * cause a change of batch before the read is finished.
-			 */
-			ad->new_batch = 0;
-		}
-		ad->batch_data_dir = REQ_ASYNC;
-		ad->current_write_count = ad->write_batch_count;
-		ad->write_batch_idled = 0;
-		arq = ad->next_arq[ad->batch_data_dir];
-		goto dispatch_request;
-	}
-
-	BUG();
-	return 0;
-
-dispatch_request:
-	/*
-	 * If a request has expired, service it.
-	 */
-
-	if (as_fifo_expired(ad, ad->batch_data_dir)) {
-fifo_expired:
-		arq = list_entry_fifo(ad->fifo_list[ad->batch_data_dir].next);
-		BUG_ON(arq == NULL);
-	}
-
-	if (ad->changed_batch) {
-		WARN_ON(ad->new_batch);
-
-		if (ad->nr_dispatched)
-			return 0;
-
-		if (ad->batch_data_dir == REQ_ASYNC)
-			ad->current_batch_expires = jiffies +
-					ad->batch_expire[REQ_ASYNC];
-		else
-			ad->new_batch = 1;
-
-		ad->changed_batch = 0;
-	}
-
-	/*
-	 * arq is the selected appropriate request.
-	 */
-	as_move_to_dispatch(ad, arq);
-
-	return 1;
-}
-
-/*
- * Add arq to a list behind alias
- */
-static inline void
-as_add_aliased_request(struct as_data *ad, struct as_rq *arq, struct as_rq *alias)
-{
-	struct request  *req = arq->request;
-	struct list_head *insert = alias->request->queuelist.prev;
-
-	/*
-	 * Transfer list of aliases
-	 */
-	while (!list_empty(&req->queuelist)) {
-		struct request *__rq = list_entry_rq(req->queuelist.next);
-		struct as_rq *__arq = RQ_DATA(__rq);
-
-		list_move_tail(&__rq->queuelist, &alias->request->queuelist);
-
-		WARN_ON(__arq->state != AS_RQ_QUEUED);
-	}
-
-	/*
-	 * Another request with the same start sector on the rbtree.
-	 * Link this request to that sector. They are untangled in
-	 * as_move_to_dispatch
-	 */
-	list_add(&arq->request->queuelist, insert);
-
-	/*
-	 * Don't want to have to handle merges.
-	 */
-	as_del_arq_hash(arq);
-	arq->request->flags |= REQ_NOMERGE;
-}
-
-/*
- * add arq to rbtree and fifo
- */
-static void as_add_request(request_queue_t *q, struct request *rq)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	struct as_rq *arq = RQ_DATA(rq);
-	struct as_rq *alias;
-	int data_dir;
-
-	if (arq->state != AS_RQ_PRESCHED) {
-		printk("arq->state: %d\n", arq->state);
-		WARN_ON(1);
-	}
-	arq->state = AS_RQ_NEW;
-
-	if (rq_data_dir(arq->request) == READ
-			|| current->flags&PF_SYNCWRITE)
-		arq->is_sync = 1;
-	else
-		arq->is_sync = 0;
-	data_dir = arq->is_sync;
-
-	arq->io_context = as_get_io_context();
-
-	if (arq->io_context) {
-		as_update_iohist(ad, arq->io_context->aic, arq->request);
-		atomic_inc(&arq->io_context->aic->nr_queued);
-	}
-
-	alias = as_add_arq_rb(ad, arq);
-	if (!alias) {
-		/*
-		 * set expire time (only used for reads) and add to fifo list
-		 */
-		arq->expires = jiffies + ad->fifo_expire[data_dir];
-		list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]);
-
-		if (rq_mergeable(arq->request))
-			as_add_arq_hash(ad, arq);
-		as_update_arq(ad, arq); /* keep state machine up to date */
-
-	} else {
-		as_add_aliased_request(ad, arq, alias);
-
-		/*
-		 * have we been anticipating this request?
-		 * or does it come from the same process as the one we are
-		 * anticipating for?
-		 */
-		if (ad->antic_status == ANTIC_WAIT_REQ
-				|| ad->antic_status == ANTIC_WAIT_NEXT) {
-			if (as_can_break_anticipation(ad, arq))
-				as_antic_stop(ad);
-		}
-	}
-
-	arq->state = AS_RQ_QUEUED;
-}
-
-static void as_activate_request(request_queue_t *q, struct request *rq)
-{
-	struct as_rq *arq = RQ_DATA(rq);
-
-	WARN_ON(arq->state != AS_RQ_DISPATCHED);
-	arq->state = AS_RQ_REMOVED;
-	if (arq->io_context && arq->io_context->aic)
-		atomic_dec(&arq->io_context->aic->nr_dispatched);
-}
-
-static void as_deactivate_request(request_queue_t *q, struct request *rq)
-{
-	struct as_rq *arq = RQ_DATA(rq);
-
-	WARN_ON(arq->state != AS_RQ_REMOVED);
-	arq->state = AS_RQ_DISPATCHED;
-	if (arq->io_context && arq->io_context->aic)
-		atomic_inc(&arq->io_context->aic->nr_dispatched);
-}
-
-/*
- * as_queue_empty tells us if there are requests left in the device. It may
- * not be the case that a driver can get the next request even if the queue
- * is not empty - it is used in the block layer to check for plugging and
- * merging opportunities
- */
-static int as_queue_empty(request_queue_t *q)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-
-	return list_empty(&ad->fifo_list[REQ_ASYNC])
-		&& list_empty(&ad->fifo_list[REQ_SYNC]);
-}
-
-static struct request *
-as_former_request(request_queue_t *q, struct request *rq)
-{
-	struct as_rq *arq = RQ_DATA(rq);
-	struct rb_node *rbprev = rb_prev(&arq->rb_node);
-	struct request *ret = NULL;
-
-	if (rbprev)
-		ret = rb_entry_arq(rbprev)->request;
-
-	return ret;
-}
-
-static struct request *
-as_latter_request(request_queue_t *q, struct request *rq)
-{
-	struct as_rq *arq = RQ_DATA(rq);
-	struct rb_node *rbnext = rb_next(&arq->rb_node);
-	struct request *ret = NULL;
-
-	if (rbnext)
-		ret = rb_entry_arq(rbnext)->request;
-
-	return ret;
-}
-
-static int
-as_merge(request_queue_t *q, struct request **req, struct bio *bio)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	sector_t rb_key = bio->bi_sector + bio_sectors(bio);
-	struct request *__rq;
-	int ret;
-
-	/*
-	 * see if the merge hash can satisfy a back merge
-	 */
-	__rq = as_find_arq_hash(ad, bio->bi_sector);
-	if (__rq) {
-		BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector);
-
-		if (elv_rq_merge_ok(__rq, bio)) {
-			ret = ELEVATOR_BACK_MERGE;
-			goto out;
-		}
-	}
-
-	/*
-	 * check for front merge
-	 */
-	__rq = as_find_arq_rb(ad, rb_key, bio_data_dir(bio));
-	if (__rq) {
-		BUG_ON(rb_key != rq_rb_key(__rq));
-
-		if (elv_rq_merge_ok(__rq, bio)) {
-			ret = ELEVATOR_FRONT_MERGE;
-			goto out;
-		}
-	}
-
-	return ELEVATOR_NO_MERGE;
-out:
-	if (ret) {
-		if (rq_mergeable(__rq))
-			as_hot_arq_hash(ad, RQ_DATA(__rq));
-	}
-	*req = __rq;
-	return ret;
-}
-
-static void as_merged_request(request_queue_t *q, struct request *req)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	struct as_rq *arq = RQ_DATA(req);
-
-	/*
-	 * hash always needs to be repositioned, key is end sector
-	 */
-	as_del_arq_hash(arq);
-	as_add_arq_hash(ad, arq);
-
-	/*
-	 * if the merge was a front merge, we need to reposition request
-	 */
-	if (rq_rb_key(req) != arq->rb_key) {
-		struct as_rq *alias, *next_arq = NULL;
-
-		if (ad->next_arq[arq->is_sync] == arq)
-			next_arq = as_find_next_arq(ad, arq);
-
-		/*
-		 * Note! We should really be moving any old aliased requests
-		 * off this request and try to insert them into the rbtree. We
-		 * currently don't bother. Ditto the next function.
-		 */
-		as_del_arq_rb(ad, arq);
-		if ((alias = as_add_arq_rb(ad, arq)) ) {
-			list_del_init(&arq->fifo);
-			as_add_aliased_request(ad, arq, alias);
-			if (next_arq)
-				ad->next_arq[arq->is_sync] = next_arq;
-		}
-		/*
-		 * Note! At this stage of this and the next function, our next
-		 * request may not be optimal - eg the request may have "grown"
-		 * behind the disk head. We currently don't bother adjusting.
-		 */
-	}
-}
-
-static void
-as_merged_requests(request_queue_t *q, struct request *req,
-			 struct request *next)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	struct as_rq *arq = RQ_DATA(req);
-	struct as_rq *anext = RQ_DATA(next);
-
-	BUG_ON(!arq);
-	BUG_ON(!anext);
-
-	/*
-	 * reposition arq (this is the merged request) in hash, and in rbtree
-	 * in case of a front merge
-	 */
-	as_del_arq_hash(arq);
-	as_add_arq_hash(ad, arq);
-
-	if (rq_rb_key(req) != arq->rb_key) {
-		struct as_rq *alias, *next_arq = NULL;
-
-		if (ad->next_arq[arq->is_sync] == arq)
-			next_arq = as_find_next_arq(ad, arq);
-
-		as_del_arq_rb(ad, arq);
-		if ((alias = as_add_arq_rb(ad, arq)) ) {
-			list_del_init(&arq->fifo);
-			as_add_aliased_request(ad, arq, alias);
-			if (next_arq)
-				ad->next_arq[arq->is_sync] = next_arq;
-		}
-	}
-
-	/*
-	 * if anext expires before arq, assign its expire time to arq
-	 * and move into anext position (anext will be deleted) in fifo
-	 */
-	if (!list_empty(&arq->fifo) && !list_empty(&anext->fifo)) {
-		if (time_before(anext->expires, arq->expires)) {
-			list_move(&arq->fifo, &anext->fifo);
-			arq->expires = anext->expires;
-			/*
-			 * Don't copy here but swap, because when anext is
-			 * removed below, it must contain the unused context
-			 */
-			swap_io_context(&arq->io_context, &anext->io_context);
-		}
-	}
-
-	/*
-	 * Transfer list of aliases
-	 */
-	while (!list_empty(&next->queuelist)) {
-		struct request *__rq = list_entry_rq(next->queuelist.next);
-		struct as_rq *__arq = RQ_DATA(__rq);
-
-		list_move_tail(&__rq->queuelist, &req->queuelist);
-
-		WARN_ON(__arq->state != AS_RQ_QUEUED);
-	}
-
-	/*
-	 * kill knowledge of next, this one is a goner
-	 */
-	as_remove_queued_request(q, next);
-	as_put_io_context(anext);
-
-	anext->state = AS_RQ_MERGED;
-}
-
-/*
- * This is executed in a "deferred" process context, by kblockd. It calls the
- * driver's request_fn so the driver can submit that request.
- *
- * IMPORTANT! This guy will reenter the elevator, so set up all queue global
- * state before calling, and don't rely on any state over calls.
- *
- * FIXME! dispatch queue is not a queue at all!
- */
-static void as_work_handler(void *data)
-{
-	struct request_queue *q = data;
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	if (!as_queue_empty(q))
-		q->request_fn(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-static void as_put_request(request_queue_t *q, struct request *rq)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	struct as_rq *arq = RQ_DATA(rq);
-
-	if (!arq) {
-		WARN_ON(1);
-		return;
-	}
-
-	if (unlikely(arq->state != AS_RQ_POSTSCHED &&
-		     arq->state != AS_RQ_PRESCHED &&
-		     arq->state != AS_RQ_MERGED)) {
-		printk("arq->state %d\n", arq->state);
-		WARN_ON(1);
-	}
-
-	mempool_free(arq, ad->arq_pool);
-	rq->elevator_private = NULL;
-}
-
-static int as_set_request(request_queue_t *q, struct request *rq,
-			  struct bio *bio, gfp_t gfp_mask)
-{
-	struct as_data *ad = q->elevator->elevator_data;
-	struct as_rq *arq = mempool_alloc(ad->arq_pool, gfp_mask);
-
-	if (arq) {
-		memset(arq, 0, sizeof(*arq));
-		RB_CLEAR(&arq->rb_node);
-		arq->request = rq;
-		arq->state = AS_RQ_PRESCHED;
-		arq->io_context = NULL;
-		INIT_LIST_HEAD(&arq->hash);
-		arq->on_hash = 0;
-		INIT_LIST_HEAD(&arq->fifo);
-		rq->elevator_private = arq;
-		return 0;
-	}
-
-	return 1;
-}
-
-static int as_may_queue(request_queue_t *q, int rw, struct bio *bio)
-{
-	int ret = ELV_MQUEUE_MAY;
-	struct as_data *ad = q->elevator->elevator_data;
-	struct io_context *ioc;
-	if (ad->antic_status == ANTIC_WAIT_REQ ||
-			ad->antic_status == ANTIC_WAIT_NEXT) {
-		ioc = as_get_io_context();
-		if (ad->io_context == ioc)
-			ret = ELV_MQUEUE_MUST;
-		put_io_context(ioc);
-	}
-
-	return ret;
-}
-
-static void as_exit_queue(elevator_t *e)
-{
-	struct as_data *ad = e->elevator_data;
-
-	del_timer_sync(&ad->antic_timer);
-	kblockd_flush();
-
-	BUG_ON(!list_empty(&ad->fifo_list[REQ_SYNC]));
-	BUG_ON(!list_empty(&ad->fifo_list[REQ_ASYNC]));
-
-	mempool_destroy(ad->arq_pool);
-	put_io_context(ad->io_context);
-	kfree(ad->hash);
-	kfree(ad);
-}
-
-/*
- * initialize elevator private data (as_data), and alloc a arq for
- * each request on the free lists
- */
-static int as_init_queue(request_queue_t *q, elevator_t *e)
-{
-	struct as_data *ad;
-	int i;
-
-	if (!arq_pool)
-		return -ENOMEM;
-
-	ad = kmalloc_node(sizeof(*ad), GFP_KERNEL, q->node);
-	if (!ad)
-		return -ENOMEM;
-	memset(ad, 0, sizeof(*ad));
-
-	ad->q = q; /* Identify what queue the data belongs to */
-
-	ad->hash = kmalloc_node(sizeof(struct list_head)*AS_HASH_ENTRIES,
-				GFP_KERNEL, q->node);
-	if (!ad->hash) {
-		kfree(ad);
-		return -ENOMEM;
-	}
-
-	ad->arq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
-				mempool_free_slab, arq_pool, q->node);
-	if (!ad->arq_pool) {
-		kfree(ad->hash);
-		kfree(ad);
-		return -ENOMEM;
-	}
-
-	/* anticipatory scheduling helpers */
-	ad->antic_timer.function = as_antic_timeout;
-	ad->antic_timer.data = (unsigned long)q;
-	init_timer(&ad->antic_timer);
-	INIT_WORK(&ad->antic_work, as_work_handler, q);
-
-	for (i = 0; i < AS_HASH_ENTRIES; i++)
-		INIT_LIST_HEAD(&ad->hash[i]);
-
-	INIT_LIST_HEAD(&ad->fifo_list[REQ_SYNC]);
-	INIT_LIST_HEAD(&ad->fifo_list[REQ_ASYNC]);
-	ad->sort_list[REQ_SYNC] = RB_ROOT;
-	ad->sort_list[REQ_ASYNC] = RB_ROOT;
-	ad->fifo_expire[REQ_SYNC] = default_read_expire;
-	ad->fifo_expire[REQ_ASYNC] = default_write_expire;
-	ad->antic_expire = default_antic_expire;
-	ad->batch_expire[REQ_SYNC] = default_read_batch_expire;
-	ad->batch_expire[REQ_ASYNC] = default_write_batch_expire;
-	e->elevator_data = ad;
-
-	ad->current_batch_expires = jiffies + ad->batch_expire[REQ_SYNC];
-	ad->write_batch_count = ad->batch_expire[REQ_ASYNC] / 10;
-	if (ad->write_batch_count < 2)
-		ad->write_batch_count = 2;
-
-	return 0;
-}
-
-/*
- * sysfs parts below
- */
-struct as_fs_entry {
-	struct attribute attr;
-	ssize_t (*show)(struct as_data *, char *);
-	ssize_t (*store)(struct as_data *, const char *, size_t);
-};
-
-static ssize_t
-as_var_show(unsigned int var, char *page)
-{
-	return sprintf(page, "%d\n", var);
-}
-
-static ssize_t
-as_var_store(unsigned long *var, const char *page, size_t count)
-{
-	char *p = (char *) page;
-
-	*var = simple_strtoul(p, &p, 10);
-	return count;
-}
-
-static ssize_t as_est_show(struct as_data *ad, char *page)
-{
-	int pos = 0;
-
-	pos += sprintf(page+pos, "%lu %% exit probability\n", 100*ad->exit_prob/256);
-	pos += sprintf(page+pos, "%lu ms new thinktime\n", ad->new_ttime_mean);
-	pos += sprintf(page+pos, "%llu sectors new seek distance\n", (unsigned long long)ad->new_seek_mean);
-
-	return pos;
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR)				\
-static ssize_t __FUNC(struct as_data *ad, char *page)		\
-{								\
-	return as_var_show(jiffies_to_msecs((__VAR)), (page));	\
-}
-SHOW_FUNCTION(as_readexpire_show, ad->fifo_expire[REQ_SYNC]);
-SHOW_FUNCTION(as_writeexpire_show, ad->fifo_expire[REQ_ASYNC]);
-SHOW_FUNCTION(as_anticexpire_show, ad->antic_expire);
-SHOW_FUNCTION(as_read_batchexpire_show, ad->batch_expire[REQ_SYNC]);
-SHOW_FUNCTION(as_write_batchexpire_show, ad->batch_expire[REQ_ASYNC]);
-#undef SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX)				\
-static ssize_t __FUNC(struct as_data *ad, const char *page, size_t count)	\
-{									\
-	int ret = as_var_store(__PTR, (page), count);		\
-	if (*(__PTR) < (MIN))						\
-		*(__PTR) = (MIN);					\
-	else if (*(__PTR) > (MAX))					\
-		*(__PTR) = (MAX);					\
-	*(__PTR) = msecs_to_jiffies(*(__PTR));				\
-	return ret;							\
-}
-STORE_FUNCTION(as_readexpire_store, &ad->fifo_expire[REQ_SYNC], 0, INT_MAX);
-STORE_FUNCTION(as_writeexpire_store, &ad->fifo_expire[REQ_ASYNC], 0, INT_MAX);
-STORE_FUNCTION(as_anticexpire_store, &ad->antic_expire, 0, INT_MAX);
-STORE_FUNCTION(as_read_batchexpire_store,
-			&ad->batch_expire[REQ_SYNC], 0, INT_MAX);
-STORE_FUNCTION(as_write_batchexpire_store,
-			&ad->batch_expire[REQ_ASYNC], 0, INT_MAX);
-#undef STORE_FUNCTION
-
-static struct as_fs_entry as_est_entry = {
-	.attr = {.name = "est_time", .mode = S_IRUGO },
-	.show = as_est_show,
-};
-static struct as_fs_entry as_readexpire_entry = {
-	.attr = {.name = "read_expire", .mode = S_IRUGO | S_IWUSR },
-	.show = as_readexpire_show,
-	.store = as_readexpire_store,
-};
-static struct as_fs_entry as_writeexpire_entry = {
-	.attr = {.name = "write_expire", .mode = S_IRUGO | S_IWUSR },
-	.show = as_writeexpire_show,
-	.store = as_writeexpire_store,
-};
-static struct as_fs_entry as_anticexpire_entry = {
-	.attr = {.name = "antic_expire", .mode = S_IRUGO | S_IWUSR },
-	.show = as_anticexpire_show,
-	.store = as_anticexpire_store,
-};
-static struct as_fs_entry as_read_batchexpire_entry = {
-	.attr = {.name = "read_batch_expire", .mode = S_IRUGO | S_IWUSR },
-	.show = as_read_batchexpire_show,
-	.store = as_read_batchexpire_store,
-};
-static struct as_fs_entry as_write_batchexpire_entry = {
-	.attr = {.name = "write_batch_expire", .mode = S_IRUGO | S_IWUSR },
-	.show = as_write_batchexpire_show,
-	.store = as_write_batchexpire_store,
-};
-
-static struct attribute *default_attrs[] = {
-	&as_est_entry.attr,
-	&as_readexpire_entry.attr,
-	&as_writeexpire_entry.attr,
-	&as_anticexpire_entry.attr,
-	&as_read_batchexpire_entry.attr,
-	&as_write_batchexpire_entry.attr,
-	NULL,
-};
-
-#define to_as(atr) container_of((atr), struct as_fs_entry, attr)
-
-static ssize_t
-as_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct as_fs_entry *entry = to_as(attr);
-
-	if (!entry->show)
-		return -EIO;
-
-	return entry->show(e->elevator_data, page);
-}
-
-static ssize_t
-as_attr_store(struct kobject *kobj, struct attribute *attr,
-		    const char *page, size_t length)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct as_fs_entry *entry = to_as(attr);
-
-	if (!entry->store)
-		return -EIO;
-
-	return entry->store(e->elevator_data, page, length);
-}
-
-static struct sysfs_ops as_sysfs_ops = {
-	.show	= as_attr_show,
-	.store	= as_attr_store,
-};
-
-static struct kobj_type as_ktype = {
-	.sysfs_ops	= &as_sysfs_ops,
-	.default_attrs	= default_attrs,
-};
-
-static struct elevator_type iosched_as = {
-	.ops = {
-		.elevator_merge_fn = 		as_merge,
-		.elevator_merged_fn =		as_merged_request,
-		.elevator_merge_req_fn =	as_merged_requests,
-		.elevator_dispatch_fn =		as_dispatch_request,
-		.elevator_add_req_fn =		as_add_request,
-		.elevator_activate_req_fn =	as_activate_request,
-		.elevator_deactivate_req_fn = 	as_deactivate_request,
-		.elevator_queue_empty_fn =	as_queue_empty,
-		.elevator_completed_req_fn =	as_completed_request,
-		.elevator_former_req_fn =	as_former_request,
-		.elevator_latter_req_fn =	as_latter_request,
-		.elevator_set_req_fn =		as_set_request,
-		.elevator_put_req_fn =		as_put_request,
-		.elevator_may_queue_fn =	as_may_queue,
-		.elevator_init_fn =		as_init_queue,
-		.elevator_exit_fn =		as_exit_queue,
-	},
-
-	.elevator_ktype = &as_ktype,
-	.elevator_name = "anticipatory",
-	.elevator_owner = THIS_MODULE,
-};
-
-static int __init as_init(void)
-{
-	int ret;
-
-	arq_pool = kmem_cache_create("as_arq", sizeof(struct as_rq),
-				     0, 0, NULL, NULL);
-	if (!arq_pool)
-		return -ENOMEM;
-
-	ret = elv_register(&iosched_as);
-	if (!ret) {
-		/*
-		 * don't allow AS to get unregistered, since we would have
-		 * to browse all tasks in the system and release their
-		 * as_io_context first
-		 */
-		__module_get(THIS_MODULE);
-		return 0;
-	}
-
-	kmem_cache_destroy(arq_pool);
-	return ret;
-}
-
-static void __exit as_exit(void)
-{
-	elv_unregister(&iosched_as);
-	kmem_cache_destroy(arq_pool);
-}
-
-module_init(as_init);
-module_exit(as_exit);
-
-MODULE_AUTHOR("Nick Piggin");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("anticipatory IO scheduler");
diff --git a/drivers/block/cfq-iosched.c b/drivers/block/cfq-iosched.c
deleted file mode 100644
index ecacca9c877e..000000000000
--- a/drivers/block/cfq-iosched.c
+++ /dev/null
@@ -1,2428 +0,0 @@
-/*
- *  linux/drivers/block/cfq-iosched.c
- *
- *  CFQ, or complete fairness queueing, disk scheduler.
- *
- *  Based on ideas from a previously unfinished io
- *  scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
- *
- *  Copyright (C) 2003 Jens Axboe <axboe@suse.de>
- */
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/config.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/hash.h>
-#include <linux/rbtree.h>
-#include <linux/mempool.h>
-#include <linux/ioprio.h>
-#include <linux/writeback.h>
-
-/*
- * tunables
- */
-static int cfq_quantum = 4;		/* max queue in one round of service */
-static int cfq_queued = 8;		/* minimum rq allocate limit per-queue*/
-static int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
-static int cfq_back_max = 16 * 1024;	/* maximum backwards seek, in KiB */
-static int cfq_back_penalty = 2;	/* penalty of a backwards seek */
-
-static int cfq_slice_sync = HZ / 10;
-static int cfq_slice_async = HZ / 25;
-static int cfq_slice_async_rq = 2;
-static int cfq_slice_idle = HZ / 100;
-
-#define CFQ_IDLE_GRACE		(HZ / 10)
-#define CFQ_SLICE_SCALE		(5)
-
-#define CFQ_KEY_ASYNC		(0)
-#define CFQ_KEY_ANY		(0xffff)
-
-/*
- * disable queueing at the driver/hardware level
- */
-static int cfq_max_depth = 2;
-
-/*
- * for the hash of cfqq inside the cfqd
- */
-#define CFQ_QHASH_SHIFT		6
-#define CFQ_QHASH_ENTRIES	(1 << CFQ_QHASH_SHIFT)
-#define list_entry_qhash(entry)	hlist_entry((entry), struct cfq_queue, cfq_hash)
-
-/*
- * for the hash of crq inside the cfqq
- */
-#define CFQ_MHASH_SHIFT		6
-#define CFQ_MHASH_BLOCK(sec)	((sec) >> 3)
-#define CFQ_MHASH_ENTRIES	(1 << CFQ_MHASH_SHIFT)
-#define CFQ_MHASH_FN(sec)	hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT)
-#define rq_hash_key(rq)		((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr)	hlist_entry((ptr), struct cfq_rq, hash)
-
-#define list_entry_cfqq(ptr)	list_entry((ptr), struct cfq_queue, cfq_list)
-#define list_entry_fifo(ptr)	list_entry((ptr), struct request, queuelist)
-
-#define RQ_DATA(rq)		(rq)->elevator_private
-
-/*
- * rb-tree defines
- */
-#define RB_NONE			(2)
-#define RB_EMPTY(node)		((node)->rb_node == NULL)
-#define RB_CLEAR_COLOR(node)	(node)->rb_color = RB_NONE
-#define RB_CLEAR(node)		do {	\
-	(node)->rb_parent = NULL;	\
-	RB_CLEAR_COLOR((node));		\
-	(node)->rb_right = NULL;	\
-	(node)->rb_left = NULL;		\
-} while (0)
-#define RB_CLEAR_ROOT(root)	((root)->rb_node = NULL)
-#define rb_entry_crq(node)	rb_entry((node), struct cfq_rq, rb_node)
-#define rq_rb_key(rq)		(rq)->sector
-
-static kmem_cache_t *crq_pool;
-static kmem_cache_t *cfq_pool;
-static kmem_cache_t *cfq_ioc_pool;
-
-#define CFQ_PRIO_LISTS		IOPRIO_BE_NR
-#define cfq_class_idle(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
-#define cfq_class_be(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
-#define cfq_class_rt(cfqq)	((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
-
-#define ASYNC			(0)
-#define SYNC			(1)
-
-#define cfq_cfqq_dispatched(cfqq)	\
-	((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
-
-#define cfq_cfqq_class_sync(cfqq)	((cfqq)->key != CFQ_KEY_ASYNC)
-
-#define cfq_cfqq_sync(cfqq)		\
-	(cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
-
-/*
- * Per block device queue structure
- */
-struct cfq_data {
-	atomic_t ref;
-	request_queue_t *queue;
-
-	/*
-	 * rr list of queues with requests and the count of them
-	 */
-	struct list_head rr_list[CFQ_PRIO_LISTS];
-	struct list_head busy_rr;
-	struct list_head cur_rr;
-	struct list_head idle_rr;
-	unsigned int busy_queues;
-
-	/*
-	 * non-ordered list of empty cfqq's
-	 */
-	struct list_head empty_list;
-
-	/*
-	 * cfqq lookup hash
-	 */
-	struct hlist_head *cfq_hash;
-
-	/*
-	 * global crq hash for all queues
-	 */
-	struct hlist_head *crq_hash;
-
-	unsigned int max_queued;
-
-	mempool_t *crq_pool;
-
-	int rq_in_driver;
-
-	/*
-	 * schedule slice state info
-	 */
-	/*
-	 * idle window management
-	 */
-	struct timer_list idle_slice_timer;
-	struct work_struct unplug_work;
-
-	struct cfq_queue *active_queue;
-	struct cfq_io_context *active_cic;
-	int cur_prio, cur_end_prio;
-	unsigned int dispatch_slice;
-
-	struct timer_list idle_class_timer;
-
-	sector_t last_sector;
-	unsigned long last_end_request;
-
-	unsigned int rq_starved;
-
-	/*
-	 * tunables, see top of file
-	 */
-	unsigned int cfq_quantum;
-	unsigned int cfq_queued;
-	unsigned int cfq_fifo_expire[2];
-	unsigned int cfq_back_penalty;
-	unsigned int cfq_back_max;
-	unsigned int cfq_slice[2];
-	unsigned int cfq_slice_async_rq;
-	unsigned int cfq_slice_idle;
-	unsigned int cfq_max_depth;
-};
-
-/*
- * Per process-grouping structure
- */
-struct cfq_queue {
-	/* reference count */
-	atomic_t ref;
-	/* parent cfq_data */
-	struct cfq_data *cfqd;
-	/* cfqq lookup hash */
-	struct hlist_node cfq_hash;
-	/* hash key */
-	unsigned int key;
-	/* on either rr or empty list of cfqd */
-	struct list_head cfq_list;
-	/* sorted list of pending requests */
-	struct rb_root sort_list;
-	/* if fifo isn't expired, next request to serve */
-	struct cfq_rq *next_crq;
-	/* requests queued in sort_list */
-	int queued[2];
-	/* currently allocated requests */
-	int allocated[2];
-	/* fifo list of requests in sort_list */
-	struct list_head fifo;
-
-	unsigned long slice_start;
-	unsigned long slice_end;
-	unsigned long slice_left;
-	unsigned long service_last;
-
-	/* number of requests that are on the dispatch list */
-	int on_dispatch[2];
-
-	/* io prio of this group */
-	unsigned short ioprio, org_ioprio;
-	unsigned short ioprio_class, org_ioprio_class;
-
-	/* various state flags, see below */
-	unsigned int flags;
-};
-
-struct cfq_rq {
-	struct rb_node rb_node;
-	sector_t rb_key;
-	struct request *request;
-	struct hlist_node hash;
-
-	struct cfq_queue *cfq_queue;
-	struct cfq_io_context *io_context;
-
-	unsigned int crq_flags;
-};
-
-enum cfqq_state_flags {
-	CFQ_CFQQ_FLAG_on_rr = 0,
-	CFQ_CFQQ_FLAG_wait_request,
-	CFQ_CFQQ_FLAG_must_alloc,
-	CFQ_CFQQ_FLAG_must_alloc_slice,
-	CFQ_CFQQ_FLAG_must_dispatch,
-	CFQ_CFQQ_FLAG_fifo_expire,
-	CFQ_CFQQ_FLAG_idle_window,
-	CFQ_CFQQ_FLAG_prio_changed,
-	CFQ_CFQQ_FLAG_expired,
-};
-
-#define CFQ_CFQQ_FNS(name)						\
-static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq)		\
-{									\
-	cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name);			\
-}									\
-static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq)	\
-{									\
-	cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name);			\
-}									\
-static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq)		\
-{									\
-	return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0;	\
-}
-
-CFQ_CFQQ_FNS(on_rr);
-CFQ_CFQQ_FNS(wait_request);
-CFQ_CFQQ_FNS(must_alloc);
-CFQ_CFQQ_FNS(must_alloc_slice);
-CFQ_CFQQ_FNS(must_dispatch);
-CFQ_CFQQ_FNS(fifo_expire);
-CFQ_CFQQ_FNS(idle_window);
-CFQ_CFQQ_FNS(prio_changed);
-CFQ_CFQQ_FNS(expired);
-#undef CFQ_CFQQ_FNS
-
-enum cfq_rq_state_flags {
-	CFQ_CRQ_FLAG_is_sync = 0,
-};
-
-#define CFQ_CRQ_FNS(name)						\
-static inline void cfq_mark_crq_##name(struct cfq_rq *crq)		\
-{									\
-	crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name);			\
-}									\
-static inline void cfq_clear_crq_##name(struct cfq_rq *crq)		\
-{									\
-	crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name);			\
-}									\
-static inline int cfq_crq_##name(const struct cfq_rq *crq)		\
-{									\
-	return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0;	\
-}
-
-CFQ_CRQ_FNS(is_sync);
-#undef CFQ_CRQ_FNS
-
-static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
-static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *);
-static void cfq_put_cfqd(struct cfq_data *cfqd);
-
-#define process_sync(tsk)	((tsk)->flags & PF_SYNCWRITE)
-
-/*
- * lots of deadline iosched dupes, can be abstracted later...
- */
-static inline void cfq_del_crq_hash(struct cfq_rq *crq)
-{
-	hlist_del_init(&crq->hash);
-}
-
-static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq)
-{
-	const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request));
-
-	hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]);
-}
-
-static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset)
-{
-	struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)];
-	struct hlist_node *entry, *next;
-
-	hlist_for_each_safe(entry, next, hash_list) {
-		struct cfq_rq *crq = list_entry_hash(entry);
-		struct request *__rq = crq->request;
-
-		if (!rq_mergeable(__rq)) {
-			cfq_del_crq_hash(crq);
-			continue;
-		}
-
-		if (rq_hash_key(__rq) == offset)
-			return __rq;
-	}
-
-	return NULL;
-}
-
-/*
- * scheduler run of queue, if there are requests pending and no one in the
- * driver that will restart queueing
- */
-static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
-{
-	if (!cfqd->rq_in_driver && cfqd->busy_queues)
-		kblockd_schedule_work(&cfqd->unplug_work);
-}
-
-static int cfq_queue_empty(request_queue_t *q)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	return !cfqd->busy_queues;
-}
-
-/*
- * Lifted from AS - choose which of crq1 and crq2 that is best served now.
- * We choose the request that is closest to the head right now. Distance
- * behind the head are penalized and only allowed to a certain extent.
- */
-static struct cfq_rq *
-cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
-{
-	sector_t last, s1, s2, d1 = 0, d2 = 0;
-	int r1_wrap = 0, r2_wrap = 0;	/* requests are behind the disk head */
-	unsigned long back_max;
-
-	if (crq1 == NULL || crq1 == crq2)
-		return crq2;
-	if (crq2 == NULL)
-		return crq1;
-
-	if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2))
-		return crq1;
-	else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1))
-		return crq2;
-
-	s1 = crq1->request->sector;
-	s2 = crq2->request->sector;
-
-	last = cfqd->last_sector;
-
-	/*
-	 * by definition, 1KiB is 2 sectors
-	 */
-	back_max = cfqd->cfq_back_max * 2;
-
-	/*
-	 * Strict one way elevator _except_ in the case where we allow
-	 * short backward seeks which are biased as twice the cost of a
-	 * similar forward seek.
-	 */
-	if (s1 >= last)
-		d1 = s1 - last;
-	else if (s1 + back_max >= last)
-		d1 = (last - s1) * cfqd->cfq_back_penalty;
-	else
-		r1_wrap = 1;
-
-	if (s2 >= last)
-		d2 = s2 - last;
-	else if (s2 + back_max >= last)
-		d2 = (last - s2) * cfqd->cfq_back_penalty;
-	else
-		r2_wrap = 1;
-
-	/* Found required data */
-	if (!r1_wrap && r2_wrap)
-		return crq1;
-	else if (!r2_wrap && r1_wrap)
-		return crq2;
-	else if (r1_wrap && r2_wrap) {
-		/* both behind the head */
-		if (s1 <= s2)
-			return crq1;
-		else
-			return crq2;
-	}
-
-	/* Both requests in front of the head */
-	if (d1 < d2)
-		return crq1;
-	else if (d2 < d1)
-		return crq2;
-	else {
-		if (s1 >= s2)
-			return crq1;
-		else
-			return crq2;
-	}
-}
-
-/*
- * would be nice to take fifo expire time into account as well
- */
-static struct cfq_rq *
-cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		  struct cfq_rq *last)
-{
-	struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
-	struct rb_node *rbnext, *rbprev;
-
-	if (!(rbnext = rb_next(&last->rb_node))) {
-		rbnext = rb_first(&cfqq->sort_list);
-		if (rbnext == &last->rb_node)
-			rbnext = NULL;
-	}
-
-	rbprev = rb_prev(&last->rb_node);
-
-	if (rbprev)
-		crq_prev = rb_entry_crq(rbprev);
-	if (rbnext)
-		crq_next = rb_entry_crq(rbnext);
-
-	return cfq_choose_req(cfqd, crq_next, crq_prev);
-}
-
-static void cfq_update_next_crq(struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = crq->cfq_queue;
-
-	if (cfqq->next_crq == crq)
-		cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
-}
-
-static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
-{
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct list_head *list, *entry;
-
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-
-	list_del(&cfqq->cfq_list);
-
-	if (cfq_class_rt(cfqq))
-		list = &cfqd->cur_rr;
-	else if (cfq_class_idle(cfqq))
-		list = &cfqd->idle_rr;
-	else {
-		/*
-		 * if cfqq has requests in flight, don't allow it to be
-		 * found in cfq_set_active_queue before it has finished them.
-		 * this is done to increase fairness between a process that
-		 * has lots of io pending vs one that only generates one
-		 * sporadically or synchronously
-		 */
-		if (cfq_cfqq_dispatched(cfqq))
-			list = &cfqd->busy_rr;
-		else
-			list = &cfqd->rr_list[cfqq->ioprio];
-	}
-
-	/*
-	 * if queue was preempted, just add to front to be fair. busy_rr
-	 * isn't sorted.
-	 */
-	if (preempted || list == &cfqd->busy_rr) {
-		list_add(&cfqq->cfq_list, list);
-		return;
-	}
-
-	/*
-	 * sort by when queue was last serviced
-	 */
-	entry = list;
-	while ((entry = entry->prev) != list) {
-		struct cfq_queue *__cfqq = list_entry_cfqq(entry);
-
-		if (!__cfqq->service_last)
-			break;
-		if (time_before(__cfqq->service_last, cfqq->service_last))
-			break;
-	}
-
-	list_add(&cfqq->cfq_list, entry);
-}
-
-/*
- * add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to last request service
- */
-static inline void
-cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	BUG_ON(cfq_cfqq_on_rr(cfqq));
-	cfq_mark_cfqq_on_rr(cfqq);
-	cfqd->busy_queues++;
-
-	cfq_resort_rr_list(cfqq, 0);
-}
-
-static inline void
-cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	BUG_ON(!cfq_cfqq_on_rr(cfqq));
-	cfq_clear_cfqq_on_rr(cfqq);
-	list_move(&cfqq->cfq_list, &cfqd->empty_list);
-
-	BUG_ON(!cfqd->busy_queues);
-	cfqd->busy_queues--;
-}
-
-/*
- * rb tree support functions
- */
-static inline void cfq_del_crq_rb(struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = crq->cfq_queue;
-	struct cfq_data *cfqd = cfqq->cfqd;
-	const int sync = cfq_crq_is_sync(crq);
-
-	BUG_ON(!cfqq->queued[sync]);
-	cfqq->queued[sync]--;
-
-	cfq_update_next_crq(crq);
-
-	rb_erase(&crq->rb_node, &cfqq->sort_list);
-	RB_CLEAR_COLOR(&crq->rb_node);
-
-	if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY(&cfqq->sort_list))
-		cfq_del_cfqq_rr(cfqd, cfqq);
-}
-
-static struct cfq_rq *
-__cfq_add_crq_rb(struct cfq_rq *crq)
-{
-	struct rb_node **p = &crq->cfq_queue->sort_list.rb_node;
-	struct rb_node *parent = NULL;
-	struct cfq_rq *__crq;
-
-	while (*p) {
-		parent = *p;
-		__crq = rb_entry_crq(parent);
-
-		if (crq->rb_key < __crq->rb_key)
-			p = &(*p)->rb_left;
-		else if (crq->rb_key > __crq->rb_key)
-			p = &(*p)->rb_right;
-		else
-			return __crq;
-	}
-
-	rb_link_node(&crq->rb_node, parent, p);
-	return NULL;
-}
-
-static void cfq_add_crq_rb(struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = crq->cfq_queue;
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct request *rq = crq->request;
-	struct cfq_rq *__alias;
-
-	crq->rb_key = rq_rb_key(rq);
-	cfqq->queued[cfq_crq_is_sync(crq)]++;
-
-	/*
-	 * looks a little odd, but the first insert might return an alias.
-	 * if that happens, put the alias on the dispatch list
-	 */
-	while ((__alias = __cfq_add_crq_rb(crq)) != NULL)
-		cfq_dispatch_insert(cfqd->queue, __alias);
-
-	rb_insert_color(&crq->rb_node, &cfqq->sort_list);
-
-	if (!cfq_cfqq_on_rr(cfqq))
-		cfq_add_cfqq_rr(cfqd, cfqq);
-
-	/*
-	 * check if this request is a better next-serve candidate
-	 */
-	cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
-}
-
-static inline void
-cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
-{
-	rb_erase(&crq->rb_node, &cfqq->sort_list);
-	cfqq->queued[cfq_crq_is_sync(crq)]--;
-
-	cfq_add_crq_rb(crq);
-}
-
-static struct request *cfq_find_rq_rb(struct cfq_data *cfqd, sector_t sector)
-
-{
-	struct cfq_queue *cfqq = cfq_find_cfq_hash(cfqd, current->pid, CFQ_KEY_ANY);
-	struct rb_node *n;
-
-	if (!cfqq)
-		goto out;
-
-	n = cfqq->sort_list.rb_node;
-	while (n) {
-		struct cfq_rq *crq = rb_entry_crq(n);
-
-		if (sector < crq->rb_key)
-			n = n->rb_left;
-		else if (sector > crq->rb_key)
-			n = n->rb_right;
-		else
-			return crq->request;
-	}
-
-out:
-	return NULL;
-}
-
-static void cfq_activate_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	cfqd->rq_in_driver++;
-}
-
-static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-
-	WARN_ON(!cfqd->rq_in_driver);
-	cfqd->rq_in_driver--;
-}
-
-static void cfq_remove_request(struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-
-	list_del_init(&rq->queuelist);
-	cfq_del_crq_rb(crq);
-	cfq_del_crq_hash(crq);
-}
-
-static int
-cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct request *__rq;
-	int ret;
-
-	__rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
-	if (__rq && elv_rq_merge_ok(__rq, bio)) {
-		ret = ELEVATOR_BACK_MERGE;
-		goto out;
-	}
-
-	__rq = cfq_find_rq_rb(cfqd, bio->bi_sector + bio_sectors(bio));
-	if (__rq && elv_rq_merge_ok(__rq, bio)) {
-		ret = ELEVATOR_FRONT_MERGE;
-		goto out;
-	}
-
-	return ELEVATOR_NO_MERGE;
-out:
-	*req = __rq;
-	return ret;
-}
-
-static void cfq_merged_request(request_queue_t *q, struct request *req)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_rq *crq = RQ_DATA(req);
-
-	cfq_del_crq_hash(crq);
-	cfq_add_crq_hash(cfqd, crq);
-
-	if (rq_rb_key(req) != crq->rb_key) {
-		struct cfq_queue *cfqq = crq->cfq_queue;
-
-		cfq_update_next_crq(crq);
-		cfq_reposition_crq_rb(cfqq, crq);
-	}
-}
-
-static void
-cfq_merged_requests(request_queue_t *q, struct request *rq,
-		    struct request *next)
-{
-	cfq_merged_request(q, rq);
-
-	/*
-	 * reposition in fifo if next is older than rq
-	 */
-	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
-	    time_before(next->start_time, rq->start_time))
-		list_move(&rq->queuelist, &next->queuelist);
-
-	cfq_remove_request(next);
-}
-
-static inline void
-__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	if (cfqq) {
-		/*
-		 * stop potential idle class queues waiting service
-		 */
-		del_timer(&cfqd->idle_class_timer);
-
-		cfqq->slice_start = jiffies;
-		cfqq->slice_end = 0;
-		cfqq->slice_left = 0;
-		cfq_clear_cfqq_must_alloc_slice(cfqq);
-		cfq_clear_cfqq_fifo_expire(cfqq);
-		cfq_clear_cfqq_expired(cfqq);
-	}
-
-	cfqd->active_queue = cfqq;
-}
-
-/*
- * 0
- * 0,1
- * 0,1,2
- * 0,1,2,3
- * 0,1,2,3,4
- * 0,1,2,3,4,5
- * 0,1,2,3,4,5,6
- * 0,1,2,3,4,5,6,7
- */
-static int cfq_get_next_prio_level(struct cfq_data *cfqd)
-{
-	int prio, wrap;
-
-	prio = -1;
-	wrap = 0;
-	do {
-		int p;
-
-		for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
-			if (!list_empty(&cfqd->rr_list[p])) {
-				prio = p;
-				break;
-			}
-		}
-
-		if (prio != -1)
-			break;
-		cfqd->cur_prio = 0;
-		if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
-			cfqd->cur_end_prio = 0;
-			if (wrap)
-				break;
-			wrap = 1;
-		}
-	} while (1);
-
-	if (unlikely(prio == -1))
-		return -1;
-
-	BUG_ON(prio >= CFQ_PRIO_LISTS);
-
-	list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
-
-	cfqd->cur_prio = prio + 1;
-	if (cfqd->cur_prio > cfqd->cur_end_prio) {
-		cfqd->cur_end_prio = cfqd->cur_prio;
-		cfqd->cur_prio = 0;
-	}
-	if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
-		cfqd->cur_prio = 0;
-		cfqd->cur_end_prio = 0;
-	}
-
-	return prio;
-}
-
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
-{
-	struct cfq_queue *cfqq;
-
-	/*
-	 * if current queue is expired but not done with its requests yet,
-	 * wait for that to happen
-	 */
-	if ((cfqq = cfqd->active_queue) != NULL) {
-		if (cfq_cfqq_expired(cfqq) && cfq_cfqq_dispatched(cfqq))
-			return NULL;
-	}
-
-	/*
-	 * if current list is non-empty, grab first entry. if it is empty,
-	 * get next prio level and grab first entry then if any are spliced
-	 */
-	if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
-		cfqq = list_entry_cfqq(cfqd->cur_rr.next);
-
-	/*
-	 * if we have idle queues and no rt or be queues had pending
-	 * requests, either allow immediate service if the grace period
-	 * has passed or arm the idle grace timer
-	 */
-	if (!cfqq && !list_empty(&cfqd->idle_rr)) {
-		unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
-
-		if (time_after_eq(jiffies, end))
-			cfqq = list_entry_cfqq(cfqd->idle_rr.next);
-		else
-			mod_timer(&cfqd->idle_class_timer, end);
-	}
-
-	__cfq_set_active_queue(cfqd, cfqq);
-	return cfqq;
-}
-
-/*
- * current cfqq expired its slice (or was too idle), select new one
- */
-static void
-__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		    int preempted)
-{
-	unsigned long now = jiffies;
-
-	if (cfq_cfqq_wait_request(cfqq))
-		del_timer(&cfqd->idle_slice_timer);
-
-	if (!preempted && !cfq_cfqq_dispatched(cfqq))
-		cfqq->service_last = now;
-
-	cfq_clear_cfqq_must_dispatch(cfqq);
-	cfq_clear_cfqq_wait_request(cfqq);
-
-	/*
-	 * store what was left of this slice, if the queue idled out
-	 * or was preempted
-	 */
-	if (time_after(now, cfqq->slice_end))
-		cfqq->slice_left = now - cfqq->slice_end;
-	else
-		cfqq->slice_left = 0;
-
-	if (cfq_cfqq_on_rr(cfqq))
-		cfq_resort_rr_list(cfqq, preempted);
-
-	if (cfqq == cfqd->active_queue)
-		cfqd->active_queue = NULL;
-
-	if (cfqd->active_cic) {
-		put_io_context(cfqd->active_cic->ioc);
-		cfqd->active_cic = NULL;
-	}
-
-	cfqd->dispatch_slice = 0;
-}
-
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
-{
-	struct cfq_queue *cfqq = cfqd->active_queue;
-
-	if (cfqq) {
-		/*
-		 * use deferred expiry, if there are requests in progress as
-		 * not to disturb the slice of the next queue
-		 */
-		if (cfq_cfqq_dispatched(cfqq))
-			cfq_mark_cfqq_expired(cfqq);
-		else
-			__cfq_slice_expired(cfqd, cfqq, preempted);
-	}
-}
-
-static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-
-{
-	WARN_ON(!RB_EMPTY(&cfqq->sort_list));
-	WARN_ON(cfqq != cfqd->active_queue);
-
-	/*
-	 * idle is disabled, either manually or by past process history
-	 */
-	if (!cfqd->cfq_slice_idle)
-		return 0;
-	if (!cfq_cfqq_idle_window(cfqq))
-		return 0;
-	/*
-	 * task has exited, don't wait
-	 */
-	if (cfqd->active_cic && !cfqd->active_cic->ioc->task)
-		return 0;
-
-	cfq_mark_cfqq_must_dispatch(cfqq);
-	cfq_mark_cfqq_wait_request(cfqq);
-
-	if (!timer_pending(&cfqd->idle_slice_timer)) {
-		unsigned long slice_left = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
-
-		cfqd->idle_slice_timer.expires = jiffies + slice_left;
-		add_timer(&cfqd->idle_slice_timer);
-	}
-
-	return 1;
-}
-
-static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq = crq->cfq_queue;
-
-	cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
-	cfq_remove_request(crq->request);
-	cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
-	elv_dispatch_sort(q, crq->request);
-}
-
-/*
- * return expired entry, or NULL to just start from scratch in rbtree
- */
-static inline struct cfq_rq *cfq_check_fifo(struct cfq_queue *cfqq)
-{
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct request *rq;
-	struct cfq_rq *crq;
-
-	if (cfq_cfqq_fifo_expire(cfqq))
-		return NULL;
-
-	if (!list_empty(&cfqq->fifo)) {
-		int fifo = cfq_cfqq_class_sync(cfqq);
-
-		crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next));
-		rq = crq->request;
-		if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
-			cfq_mark_cfqq_fifo_expire(cfqq);
-			return crq;
-		}
-	}
-
-	return NULL;
-}
-
-/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
- */
-static inline int
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
-
-	WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
-
-	return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
-}
-
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
-}
-
-static inline int
-cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	const int base_rq = cfqd->cfq_slice_async_rq;
-
-	WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
-
-	return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
-}
-
-/*
- * get next queue for service
- */
-static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd, int force)
-{
-	unsigned long now = jiffies;
-	struct cfq_queue *cfqq;
-
-	cfqq = cfqd->active_queue;
-	if (!cfqq)
-		goto new_queue;
-
-	if (cfq_cfqq_expired(cfqq))
-		goto new_queue;
-
-	/*
-	 * slice has expired
-	 */
-	if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end))
-		goto expire;
-
-	/*
-	 * if queue has requests, dispatch one. if not, check if
-	 * enough slice is left to wait for one
-	 */
-	if (!RB_EMPTY(&cfqq->sort_list))
-		goto keep_queue;
-	else if (!force && cfq_cfqq_class_sync(cfqq) &&
-		 time_before(now, cfqq->slice_end)) {
-		if (cfq_arm_slice_timer(cfqd, cfqq))
-			return NULL;
-	}
-
-expire:
-	cfq_slice_expired(cfqd, 0);
-new_queue:
-	cfqq = cfq_set_active_queue(cfqd);
-keep_queue:
-	return cfqq;
-}
-
-static int
-__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-			int max_dispatch)
-{
-	int dispatched = 0;
-
-	BUG_ON(RB_EMPTY(&cfqq->sort_list));
-
-	do {
-		struct cfq_rq *crq;
-
-		/*
-		 * follow expired path, else get first next available
-		 */
-		if ((crq = cfq_check_fifo(cfqq)) == NULL)
-			crq = cfqq->next_crq;
-
-		/*
-		 * finally, insert request into driver dispatch list
-		 */
-		cfq_dispatch_insert(cfqd->queue, crq);
-
-		cfqd->dispatch_slice++;
-		dispatched++;
-
-		if (!cfqd->active_cic) {
-			atomic_inc(&crq->io_context->ioc->refcount);
-			cfqd->active_cic = crq->io_context;
-		}
-
-		if (RB_EMPTY(&cfqq->sort_list))
-			break;
-
-	} while (dispatched < max_dispatch);
-
-	/*
-	 * if slice end isn't set yet, set it. if at least one request was
-	 * sync, use the sync time slice value
-	 */
-	if (!cfqq->slice_end)
-		cfq_set_prio_slice(cfqd, cfqq);
-
-	/*
-	 * expire an async queue immediately if it has used up its slice. idle
-	 * queue always expire after 1 dispatch round.
-	 */
-	if ((!cfq_cfqq_sync(cfqq) &&
-	    cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
-	    cfq_class_idle(cfqq))
-		cfq_slice_expired(cfqd, 0);
-
-	return dispatched;
-}
-
-static int
-cfq_dispatch_requests(request_queue_t *q, int force)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq;
-
-	if (!cfqd->busy_queues)
-		return 0;
-
-	cfqq = cfq_select_queue(cfqd, force);
-	if (cfqq) {
-		int max_dispatch;
-
-		/*
-		 * if idle window is disabled, allow queue buildup
-		 */
-		if (!cfq_cfqq_idle_window(cfqq) &&
-		    cfqd->rq_in_driver >= cfqd->cfq_max_depth)
-			return 0;
-
-		cfq_clear_cfqq_must_dispatch(cfqq);
-		cfq_clear_cfqq_wait_request(cfqq);
-		del_timer(&cfqd->idle_slice_timer);
-
-		if (!force) {
-			max_dispatch = cfqd->cfq_quantum;
-			if (cfq_class_idle(cfqq))
-				max_dispatch = 1;
-		} else
-			max_dispatch = INT_MAX;
-
-		return __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
-	}
-
-	return 0;
-}
-
-/*
- * task holds one reference to the queue, dropped when task exits. each crq
- * in-flight on this queue also holds a reference, dropped when crq is freed.
- *
- * queue lock must be held here.
- */
-static void cfq_put_queue(struct cfq_queue *cfqq)
-{
-	struct cfq_data *cfqd = cfqq->cfqd;
-
-	BUG_ON(atomic_read(&cfqq->ref) <= 0);
-
-	if (!atomic_dec_and_test(&cfqq->ref))
-		return;
-
-	BUG_ON(rb_first(&cfqq->sort_list));
-	BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
-	BUG_ON(cfq_cfqq_on_rr(cfqq));
-
-	if (unlikely(cfqd->active_queue == cfqq)) {
-		__cfq_slice_expired(cfqd, cfqq, 0);
-		cfq_schedule_dispatch(cfqd);
-	}
-
-	cfq_put_cfqd(cfqq->cfqd);
-
-	/*
-	 * it's on the empty list and still hashed
-	 */
-	list_del(&cfqq->cfq_list);
-	hlist_del(&cfqq->cfq_hash);
-	kmem_cache_free(cfq_pool, cfqq);
-}
-
-static inline struct cfq_queue *
-__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
-		    const int hashval)
-{
-	struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
-	struct hlist_node *entry, *next;
-
-	hlist_for_each_safe(entry, next, hash_list) {
-		struct cfq_queue *__cfqq = list_entry_qhash(entry);
-		const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->ioprio_class, __cfqq->ioprio);
-
-		if (__cfqq->key == key && (__p == prio || prio == CFQ_KEY_ANY))
-			return __cfqq;
-	}
-
-	return NULL;
-}
-
-static struct cfq_queue *
-cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
-{
-	return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
-}
-
-static void cfq_free_io_context(struct cfq_io_context *cic)
-{
-	struct cfq_io_context *__cic;
-	struct list_head *entry, *next;
-
-	list_for_each_safe(entry, next, &cic->list) {
-		__cic = list_entry(entry, struct cfq_io_context, list);
-		kmem_cache_free(cfq_ioc_pool, __cic);
-	}
-
-	kmem_cache_free(cfq_ioc_pool, cic);
-}
-
-/*
- * Called with interrupts disabled
- */
-static void cfq_exit_single_io_context(struct cfq_io_context *cic)
-{
-	struct cfq_data *cfqd = cic->cfqq->cfqd;
-	request_queue_t *q = cfqd->queue;
-
-	WARN_ON(!irqs_disabled());
-
-	spin_lock(q->queue_lock);
-
-	if (unlikely(cic->cfqq == cfqd->active_queue)) {
-		__cfq_slice_expired(cfqd, cic->cfqq, 0);
-		cfq_schedule_dispatch(cfqd);
-	}
-
-	cfq_put_queue(cic->cfqq);
-	cic->cfqq = NULL;
-	spin_unlock(q->queue_lock);
-}
-
-/*
- * Another task may update the task cic list, if it is doing a queue lookup
- * on its behalf. cfq_cic_lock excludes such concurrent updates
- */
-static void cfq_exit_io_context(struct cfq_io_context *cic)
-{
-	struct cfq_io_context *__cic;
-	struct list_head *entry;
-	unsigned long flags;
-
-	local_irq_save(flags);
-
-	/*
-	 * put the reference this task is holding to the various queues
-	 */
-	list_for_each(entry, &cic->list) {
-		__cic = list_entry(entry, struct cfq_io_context, list);
-		cfq_exit_single_io_context(__cic);
-	}
-
-	cfq_exit_single_io_context(cic);
-	local_irq_restore(flags);
-}
-
-static struct cfq_io_context *
-cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
-{
-	struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
-
-	if (cic) {
-		INIT_LIST_HEAD(&cic->list);
-		cic->cfqq = NULL;
-		cic->key = NULL;
-		cic->last_end_request = jiffies;
-		cic->ttime_total = 0;
-		cic->ttime_samples = 0;
-		cic->ttime_mean = 0;
-		cic->dtor = cfq_free_io_context;
-		cic->exit = cfq_exit_io_context;
-	}
-
-	return cic;
-}
-
-static void cfq_init_prio_data(struct cfq_queue *cfqq)
-{
-	struct task_struct *tsk = current;
-	int ioprio_class;
-
-	if (!cfq_cfqq_prio_changed(cfqq))
-		return;
-
-	ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio);
-	switch (ioprio_class) {
-		default:
-			printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
-		case IOPRIO_CLASS_NONE:
-			/*
-			 * no prio set, place us in the middle of the BE classes
-			 */
-			cfqq->ioprio = task_nice_ioprio(tsk);
-			cfqq->ioprio_class = IOPRIO_CLASS_BE;
-			break;
-		case IOPRIO_CLASS_RT:
-			cfqq->ioprio = task_ioprio(tsk);
-			cfqq->ioprio_class = IOPRIO_CLASS_RT;
-			break;
-		case IOPRIO_CLASS_BE:
-			cfqq->ioprio = task_ioprio(tsk);
-			cfqq->ioprio_class = IOPRIO_CLASS_BE;
-			break;
-		case IOPRIO_CLASS_IDLE:
-			cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
-			cfqq->ioprio = 7;
-			cfq_clear_cfqq_idle_window(cfqq);
-			break;
-	}
-
-	/*
-	 * keep track of original prio settings in case we have to temporarily
-	 * elevate the priority of this queue
-	 */
-	cfqq->org_ioprio = cfqq->ioprio;
-	cfqq->org_ioprio_class = cfqq->ioprio_class;
-
-	if (cfq_cfqq_on_rr(cfqq))
-		cfq_resort_rr_list(cfqq, 0);
-
-	cfq_clear_cfqq_prio_changed(cfqq);
-}
-
-static inline void changed_ioprio(struct cfq_queue *cfqq)
-{
-	if (cfqq) {
-		struct cfq_data *cfqd = cfqq->cfqd;
-
-		spin_lock(cfqd->queue->queue_lock);
-		cfq_mark_cfqq_prio_changed(cfqq);
-		cfq_init_prio_data(cfqq);
-		spin_unlock(cfqd->queue->queue_lock);
-	}
-}
-
-/*
- * callback from sys_ioprio_set, irqs are disabled
- */
-static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
-{
-	struct cfq_io_context *cic = ioc->cic;
-
-	changed_ioprio(cic->cfqq);
-
-	list_for_each_entry(cic, &cic->list, list)
-		changed_ioprio(cic->cfqq);
-
-	return 0;
-}
-
-static struct cfq_queue *
-cfq_get_queue(struct cfq_data *cfqd, unsigned int key, unsigned short ioprio,
-	      gfp_t gfp_mask)
-{
-	const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
-	struct cfq_queue *cfqq, *new_cfqq = NULL;
-
-retry:
-	cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
-
-	if (!cfqq) {
-		if (new_cfqq) {
-			cfqq = new_cfqq;
-			new_cfqq = NULL;
-		} else if (gfp_mask & __GFP_WAIT) {
-			spin_unlock_irq(cfqd->queue->queue_lock);
-			new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
-			spin_lock_irq(cfqd->queue->queue_lock);
-			goto retry;
-		} else {
-			cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
-			if (!cfqq)
-				goto out;
-		}
-
-		memset(cfqq, 0, sizeof(*cfqq));
-
-		INIT_HLIST_NODE(&cfqq->cfq_hash);
-		INIT_LIST_HEAD(&cfqq->cfq_list);
-		RB_CLEAR_ROOT(&cfqq->sort_list);
-		INIT_LIST_HEAD(&cfqq->fifo);
-
-		cfqq->key = key;
-		hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
-		atomic_set(&cfqq->ref, 0);
-		cfqq->cfqd = cfqd;
-		atomic_inc(&cfqd->ref);
-		cfqq->service_last = 0;
-		/*
-		 * set ->slice_left to allow preemption for a new process
-		 */
-		cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
-		cfq_mark_cfqq_idle_window(cfqq);
-		cfq_mark_cfqq_prio_changed(cfqq);
-		cfq_init_prio_data(cfqq);
-	}
-
-	if (new_cfqq)
-		kmem_cache_free(cfq_pool, new_cfqq);
-
-	atomic_inc(&cfqq->ref);
-out:
-	WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
-	return cfqq;
-}
-
-/*
- * Setup general io context and cfq io context. There can be several cfq
- * io contexts per general io context, if this process is doing io to more
- * than one device managed by cfq. Note that caller is holding a reference to
- * cfqq, so we don't need to worry about it disappearing
- */
-static struct cfq_io_context *
-cfq_get_io_context(struct cfq_data *cfqd, pid_t pid, gfp_t gfp_mask)
-{
-	struct io_context *ioc = NULL;
-	struct cfq_io_context *cic;
-
-	might_sleep_if(gfp_mask & __GFP_WAIT);
-
-	ioc = get_io_context(gfp_mask);
-	if (!ioc)
-		return NULL;
-
-	if ((cic = ioc->cic) == NULL) {
-		cic = cfq_alloc_io_context(cfqd, gfp_mask);
-
-		if (cic == NULL)
-			goto err;
-
-		/*
-		 * manually increment generic io_context usage count, it
-		 * cannot go away since we are already holding one ref to it
-		 */
-		ioc->cic = cic;
-		ioc->set_ioprio = cfq_ioc_set_ioprio;
-		cic->ioc = ioc;
-		cic->key = cfqd;
-		atomic_inc(&cfqd->ref);
-	} else {
-		struct cfq_io_context *__cic;
-
-		/*
-		 * the first cic on the list is actually the head itself
-		 */
-		if (cic->key == cfqd)
-			goto out;
-
-		/*
-		 * cic exists, check if we already are there. linear search
-		 * should be ok here, the list will usually not be more than
-		 * 1 or a few entries long
-		 */
-		list_for_each_entry(__cic, &cic->list, list) {
-			/*
-			 * this process is already holding a reference to
-			 * this queue, so no need to get one more
-			 */
-			if (__cic->key == cfqd) {
-				cic = __cic;
-				goto out;
-			}
-		}
-
-		/*
-		 * nope, process doesn't have a cic assoicated with this
-		 * cfqq yet. get a new one and add to list
-		 */
-		__cic = cfq_alloc_io_context(cfqd, gfp_mask);
-		if (__cic == NULL)
-			goto err;
-
-		__cic->ioc = ioc;
-		__cic->key = cfqd;
-		atomic_inc(&cfqd->ref);
-		list_add(&__cic->list, &cic->list);
-		cic = __cic;
-	}
-
-out:
-	return cic;
-err:
-	put_io_context(ioc);
-	return NULL;
-}
-
-static void
-cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
-{
-	unsigned long elapsed, ttime;
-
-	/*
-	 * if this context already has stuff queued, thinktime is from
-	 * last queue not last end
-	 */
-#if 0
-	if (time_after(cic->last_end_request, cic->last_queue))
-		elapsed = jiffies - cic->last_end_request;
-	else
-		elapsed = jiffies - cic->last_queue;
-#else
-		elapsed = jiffies - cic->last_end_request;
-#endif
-
-	ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
-
-	cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
-	cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
-	cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
-}
-
-#define sample_valid(samples)	((samples) > 80)
-
-/*
- * Disable idle window if the process thinks too long or seeks so much that
- * it doesn't matter
- */
-static void
-cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		       struct cfq_io_context *cic)
-{
-	int enable_idle = cfq_cfqq_idle_window(cfqq);
-
-	if (!cic->ioc->task || !cfqd->cfq_slice_idle)
-		enable_idle = 0;
-	else if (sample_valid(cic->ttime_samples)) {
-		if (cic->ttime_mean > cfqd->cfq_slice_idle)
-			enable_idle = 0;
-		else
-			enable_idle = 1;
-	}
-
-	if (enable_idle)
-		cfq_mark_cfqq_idle_window(cfqq);
-	else
-		cfq_clear_cfqq_idle_window(cfqq);
-}
-
-
-/*
- * Check if new_cfqq should preempt the currently active queue. Return 0 for
- * no or if we aren't sure, a 1 will cause a preempt.
- */
-static int
-cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
-		   struct cfq_rq *crq)
-{
-	struct cfq_queue *cfqq = cfqd->active_queue;
-
-	if (cfq_class_idle(new_cfqq))
-		return 0;
-
-	if (!cfqq)
-		return 1;
-
-	if (cfq_class_idle(cfqq))
-		return 1;
-	if (!cfq_cfqq_wait_request(new_cfqq))
-		return 0;
-	/*
-	 * if it doesn't have slice left, forget it
-	 */
-	if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
-		return 0;
-	if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq))
-		return 1;
-
-	return 0;
-}
-
-/*
- * cfqq preempts the active queue. if we allowed preempt with no slice left,
- * let it have half of its nominal slice.
- */
-static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	struct cfq_queue *__cfqq, *next;
-
-	list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list)
-		cfq_resort_rr_list(__cfqq, 1);
-
-	if (!cfqq->slice_left)
-		cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
-
-	cfqq->slice_end = cfqq->slice_left + jiffies;
-	__cfq_slice_expired(cfqd, cfqq, 1);
-	__cfq_set_active_queue(cfqd, cfqq);
-}
-
-/*
- * should really be a ll_rw_blk.c helper
- */
-static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	request_queue_t *q = cfqd->queue;
-
-	if (!blk_queue_plugged(q))
-		q->request_fn(q);
-	else
-		__generic_unplug_device(q);
-}
-
-/*
- * Called when a new fs request (crq) is added (to cfqq). Check if there's
- * something we should do about it
- */
-static void
-cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		 struct cfq_rq *crq)
-{
-	struct cfq_io_context *cic;
-
-	cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
-
-	/*
-	 * we never wait for an async request and we don't allow preemption
-	 * of an async request. so just return early
-	 */
-	if (!cfq_crq_is_sync(crq))
-		return;
-
-	cic = crq->io_context;
-
-	cfq_update_io_thinktime(cfqd, cic);
-	cfq_update_idle_window(cfqd, cfqq, cic);
-
-	cic->last_queue = jiffies;
-
-	if (cfqq == cfqd->active_queue) {
-		/*
-		 * if we are waiting for a request for this queue, let it rip
-		 * immediately and flag that we must not expire this queue
-		 * just now
-		 */
-		if (cfq_cfqq_wait_request(cfqq)) {
-			cfq_mark_cfqq_must_dispatch(cfqq);
-			del_timer(&cfqd->idle_slice_timer);
-			cfq_start_queueing(cfqd, cfqq);
-		}
-	} else if (cfq_should_preempt(cfqd, cfqq, crq)) {
-		/*
-		 * not the active queue - expire current slice if it is
-		 * idle and has expired it's mean thinktime or this new queue
-		 * has some old slice time left and is of higher priority
-		 */
-		cfq_preempt_queue(cfqd, cfqq);
-		cfq_mark_cfqq_must_dispatch(cfqq);
-		cfq_start_queueing(cfqd, cfqq);
-	}
-}
-
-static void cfq_insert_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct cfq_queue *cfqq = crq->cfq_queue;
-
-	cfq_init_prio_data(cfqq);
-
-	cfq_add_crq_rb(crq);
-
-	list_add_tail(&rq->queuelist, &cfqq->fifo);
-
-	if (rq_mergeable(rq))
-		cfq_add_crq_hash(cfqd, crq);
-
-	cfq_crq_enqueued(cfqd, cfqq, crq);
-}
-
-static void cfq_completed_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct cfq_queue *cfqq = crq->cfq_queue;
-	struct cfq_data *cfqd = cfqq->cfqd;
-	const int sync = cfq_crq_is_sync(crq);
-	unsigned long now;
-
-	now = jiffies;
-
-	WARN_ON(!cfqd->rq_in_driver);
-	WARN_ON(!cfqq->on_dispatch[sync]);
-	cfqd->rq_in_driver--;
-	cfqq->on_dispatch[sync]--;
-
-	if (!cfq_class_idle(cfqq))
-		cfqd->last_end_request = now;
-
-	if (!cfq_cfqq_dispatched(cfqq)) {
-		if (cfq_cfqq_on_rr(cfqq)) {
-			cfqq->service_last = now;
-			cfq_resort_rr_list(cfqq, 0);
-		}
-		if (cfq_cfqq_expired(cfqq)) {
-			__cfq_slice_expired(cfqd, cfqq, 0);
-			cfq_schedule_dispatch(cfqd);
-		}
-	}
-
-	if (cfq_crq_is_sync(crq))
-		crq->io_context->last_end_request = now;
-}
-
-static struct request *
-cfq_former_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct rb_node *rbprev = rb_prev(&crq->rb_node);
-
-	if (rbprev)
-		return rb_entry_crq(rbprev)->request;
-
-	return NULL;
-}
-
-static struct request *
-cfq_latter_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_rq *crq = RQ_DATA(rq);
-	struct rb_node *rbnext = rb_next(&crq->rb_node);
-
-	if (rbnext)
-		return rb_entry_crq(rbnext)->request;
-
-	return NULL;
-}
-
-/*
- * we temporarily boost lower priority queues if they are holding fs exclusive
- * resources. they are boosted to normal prio (CLASS_BE/4)
- */
-static void cfq_prio_boost(struct cfq_queue *cfqq)
-{
-	const int ioprio_class = cfqq->ioprio_class;
-	const int ioprio = cfqq->ioprio;
-
-	if (has_fs_excl()) {
-		/*
-		 * boost idle prio on transactions that would lock out other
-		 * users of the filesystem
-		 */
-		if (cfq_class_idle(cfqq))
-			cfqq->ioprio_class = IOPRIO_CLASS_BE;
-		if (cfqq->ioprio > IOPRIO_NORM)
-			cfqq->ioprio = IOPRIO_NORM;
-	} else {
-		/*
-		 * check if we need to unboost the queue
-		 */
-		if (cfqq->ioprio_class != cfqq->org_ioprio_class)
-			cfqq->ioprio_class = cfqq->org_ioprio_class;
-		if (cfqq->ioprio != cfqq->org_ioprio)
-			cfqq->ioprio = cfqq->org_ioprio;
-	}
-
-	/*
-	 * refile between round-robin lists if we moved the priority class
-	 */
-	if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) &&
-	    cfq_cfqq_on_rr(cfqq))
-		cfq_resort_rr_list(cfqq, 0);
-}
-
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
-{
-	if (rw == READ || process_sync(task))
-		return task->pid;
-
-	return CFQ_KEY_ASYNC;
-}
-
-static inline int
-__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		struct task_struct *task, int rw)
-{
-#if 1
-	if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
-	    !cfq_cfqq_must_alloc_slice(cfqq)) {
-		cfq_mark_cfqq_must_alloc_slice(cfqq);
-		return ELV_MQUEUE_MUST;
-	}
-
-	return ELV_MQUEUE_MAY;
-#else
-	if (!cfqq || task->flags & PF_MEMALLOC)
-		return ELV_MQUEUE_MAY;
-	if (!cfqq->allocated[rw] || cfq_cfqq_must_alloc(cfqq)) {
-		if (cfq_cfqq_wait_request(cfqq))
-			return ELV_MQUEUE_MUST;
-
-		/*
-		 * only allow 1 ELV_MQUEUE_MUST per slice, otherwise we
-		 * can quickly flood the queue with writes from a single task
-		 */
-		if (rw == READ || !cfq_cfqq_must_alloc_slice(cfqq)) {
-			cfq_mark_cfqq_must_alloc_slice(cfqq);
-			return ELV_MQUEUE_MUST;
-		}
-
-		return ELV_MQUEUE_MAY;
-	}
-	if (cfq_class_idle(cfqq))
-		return ELV_MQUEUE_NO;
-	if (cfqq->allocated[rw] >= cfqd->max_queued) {
-		struct io_context *ioc = get_io_context(GFP_ATOMIC);
-		int ret = ELV_MQUEUE_NO;
-
-		if (ioc && ioc->nr_batch_requests)
-			ret = ELV_MQUEUE_MAY;
-
-		put_io_context(ioc);
-		return ret;
-	}
-
-	return ELV_MQUEUE_MAY;
-#endif
-}
-
-static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct task_struct *tsk = current;
-	struct cfq_queue *cfqq;
-
-	/*
-	 * don't force setup of a queue from here, as a call to may_queue
-	 * does not necessarily imply that a request actually will be queued.
-	 * so just lookup a possibly existing queue, or return 'may queue'
-	 * if that fails
-	 */
-	cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio);
-	if (cfqq) {
-		cfq_init_prio_data(cfqq);
-		cfq_prio_boost(cfqq);
-
-		return __cfq_may_queue(cfqd, cfqq, tsk, rw);
-	}
-
-	return ELV_MQUEUE_MAY;
-}
-
-static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct request_list *rl = &q->rq;
-
-	if (cfqq->allocated[READ] <= cfqd->max_queued || cfqd->rq_starved) {
-		smp_mb();
-		if (waitqueue_active(&rl->wait[READ]))
-			wake_up(&rl->wait[READ]);
-	}
-
-	if (cfqq->allocated[WRITE] <= cfqd->max_queued || cfqd->rq_starved) {
-		smp_mb();
-		if (waitqueue_active(&rl->wait[WRITE]))
-			wake_up(&rl->wait[WRITE]);
-	}
-}
-
-/*
- * queue lock held here
- */
-static void cfq_put_request(request_queue_t *q, struct request *rq)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_rq *crq = RQ_DATA(rq);
-
-	if (crq) {
-		struct cfq_queue *cfqq = crq->cfq_queue;
-		const int rw = rq_data_dir(rq);
-
-		BUG_ON(!cfqq->allocated[rw]);
-		cfqq->allocated[rw]--;
-
-		put_io_context(crq->io_context->ioc);
-
-		mempool_free(crq, cfqd->crq_pool);
-		rq->elevator_private = NULL;
-
-		cfq_check_waiters(q, cfqq);
-		cfq_put_queue(cfqq);
-	}
-}
-
-/*
- * Allocate cfq data structures associated with this request.
- */
-static int
-cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
-		gfp_t gfp_mask)
-{
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct task_struct *tsk = current;
-	struct cfq_io_context *cic;
-	const int rw = rq_data_dir(rq);
-	pid_t key = cfq_queue_pid(tsk, rw);
-	struct cfq_queue *cfqq;
-	struct cfq_rq *crq;
-	unsigned long flags;
-
-	might_sleep_if(gfp_mask & __GFP_WAIT);
-
-	cic = cfq_get_io_context(cfqd, key, gfp_mask);
-
-	spin_lock_irqsave(q->queue_lock, flags);
-
-	if (!cic)
-		goto queue_fail;
-
-	if (!cic->cfqq) {
-		cfqq = cfq_get_queue(cfqd, key, tsk->ioprio, gfp_mask);
-		if (!cfqq)
-			goto queue_fail;
-
-		cic->cfqq = cfqq;
-	} else
-		cfqq = cic->cfqq;
-
-	cfqq->allocated[rw]++;
-	cfq_clear_cfqq_must_alloc(cfqq);
-	cfqd->rq_starved = 0;
-	atomic_inc(&cfqq->ref);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-
-	crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
-	if (crq) {
-		RB_CLEAR(&crq->rb_node);
-		crq->rb_key = 0;
-		crq->request = rq;
-		INIT_HLIST_NODE(&crq->hash);
-		crq->cfq_queue = cfqq;
-		crq->io_context = cic;
-
-		if (rw == READ || process_sync(tsk))
-			cfq_mark_crq_is_sync(crq);
-		else
-			cfq_clear_crq_is_sync(crq);
-
-		rq->elevator_private = crq;
-		return 0;
-	}
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	cfqq->allocated[rw]--;
-	if (!(cfqq->allocated[0] + cfqq->allocated[1]))
-		cfq_mark_cfqq_must_alloc(cfqq);
-	cfq_put_queue(cfqq);
-queue_fail:
-	if (cic)
-		put_io_context(cic->ioc);
-	/*
-	 * mark us rq allocation starved. we need to kickstart the process
-	 * ourselves if there are no pending requests that can do it for us.
-	 * that would be an extremely rare OOM situation
-	 */
-	cfqd->rq_starved = 1;
-	cfq_schedule_dispatch(cfqd);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-	return 1;
-}
-
-static void cfq_kick_queue(void *data)
-{
-	request_queue_t *q = data;
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-
-	if (cfqd->rq_starved) {
-		struct request_list *rl = &q->rq;
-
-		/*
-		 * we aren't guaranteed to get a request after this, but we
-		 * have to be opportunistic
-		 */
-		smp_mb();
-		if (waitqueue_active(&rl->wait[READ]))
-			wake_up(&rl->wait[READ]);
-		if (waitqueue_active(&rl->wait[WRITE]))
-			wake_up(&rl->wait[WRITE]);
-	}
-
-	blk_remove_plug(q);
-	q->request_fn(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-/*
- * Timer running if the active_queue is currently idling inside its time slice
- */
-static void cfq_idle_slice_timer(unsigned long data)
-{
-	struct cfq_data *cfqd = (struct cfq_data *) data;
-	struct cfq_queue *cfqq;
-	unsigned long flags;
-
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
-	if ((cfqq = cfqd->active_queue) != NULL) {
-		unsigned long now = jiffies;
-
-		/*
-		 * expired
-		 */
-		if (time_after(now, cfqq->slice_end))
-			goto expire;
-
-		/*
-		 * only expire and reinvoke request handler, if there are
-		 * other queues with pending requests
-		 */
-		if (!cfqd->busy_queues) {
-			cfqd->idle_slice_timer.expires = min(now + cfqd->cfq_slice_idle, cfqq->slice_end);
-			add_timer(&cfqd->idle_slice_timer);
-			goto out_cont;
-		}
-
-		/*
-		 * not expired and it has a request pending, let it dispatch
-		 */
-		if (!RB_EMPTY(&cfqq->sort_list)) {
-			cfq_mark_cfqq_must_dispatch(cfqq);
-			goto out_kick;
-		}
-	}
-expire:
-	cfq_slice_expired(cfqd, 0);
-out_kick:
-	cfq_schedule_dispatch(cfqd);
-out_cont:
-	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-}
-
-/*
- * Timer running if an idle class queue is waiting for service
- */
-static void cfq_idle_class_timer(unsigned long data)
-{
-	struct cfq_data *cfqd = (struct cfq_data *) data;
-	unsigned long flags, end;
-
-	spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
-	/*
-	 * race with a non-idle queue, reset timer
-	 */
-	end = cfqd->last_end_request + CFQ_IDLE_GRACE;
-	if (!time_after_eq(jiffies, end)) {
-		cfqd->idle_class_timer.expires = end;
-		add_timer(&cfqd->idle_class_timer);
-	} else
-		cfq_schedule_dispatch(cfqd);
-
-	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-}
-
-static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
-{
-	del_timer_sync(&cfqd->idle_slice_timer);
-	del_timer_sync(&cfqd->idle_class_timer);
-	blk_sync_queue(cfqd->queue);
-}
-
-static void cfq_put_cfqd(struct cfq_data *cfqd)
-{
-	request_queue_t *q = cfqd->queue;
-
-	if (!atomic_dec_and_test(&cfqd->ref))
-		return;
-
-	cfq_shutdown_timer_wq(cfqd);
-	blk_put_queue(q);
-
-	mempool_destroy(cfqd->crq_pool);
-	kfree(cfqd->crq_hash);
-	kfree(cfqd->cfq_hash);
-	kfree(cfqd);
-}
-
-static void cfq_exit_queue(elevator_t *e)
-{
-	struct cfq_data *cfqd = e->elevator_data;
-
-	cfq_shutdown_timer_wq(cfqd);
-	cfq_put_cfqd(cfqd);
-}
-
-static int cfq_init_queue(request_queue_t *q, elevator_t *e)
-{
-	struct cfq_data *cfqd;
-	int i;
-
-	cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL);
-	if (!cfqd)
-		return -ENOMEM;
-
-	memset(cfqd, 0, sizeof(*cfqd));
-
-	for (i = 0; i < CFQ_PRIO_LISTS; i++)
-		INIT_LIST_HEAD(&cfqd->rr_list[i]);
-
-	INIT_LIST_HEAD(&cfqd->busy_rr);
-	INIT_LIST_HEAD(&cfqd->cur_rr);
-	INIT_LIST_HEAD(&cfqd->idle_rr);
-	INIT_LIST_HEAD(&cfqd->empty_list);
-
-	cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL);
-	if (!cfqd->crq_hash)
-		goto out_crqhash;
-
-	cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL);
-	if (!cfqd->cfq_hash)
-		goto out_cfqhash;
-
-	cfqd->crq_pool = mempool_create(BLKDEV_MIN_RQ, mempool_alloc_slab, mempool_free_slab, crq_pool);
-	if (!cfqd->crq_pool)
-		goto out_crqpool;
-
-	for (i = 0; i < CFQ_MHASH_ENTRIES; i++)
-		INIT_HLIST_HEAD(&cfqd->crq_hash[i]);
-	for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
-		INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
-
-	e->elevator_data = cfqd;
-
-	cfqd->queue = q;
-	atomic_inc(&q->refcnt);
-
-	cfqd->max_queued = q->nr_requests / 4;
-	q->nr_batching = cfq_queued;
-
-	init_timer(&cfqd->idle_slice_timer);
-	cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
-	cfqd->idle_slice_timer.data = (unsigned long) cfqd;
-
-	init_timer(&cfqd->idle_class_timer);
-	cfqd->idle_class_timer.function = cfq_idle_class_timer;
-	cfqd->idle_class_timer.data = (unsigned long) cfqd;
-
-	INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);
-
-	atomic_set(&cfqd->ref, 1);
-
-	cfqd->cfq_queued = cfq_queued;
-	cfqd->cfq_quantum = cfq_quantum;
-	cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
-	cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
-	cfqd->cfq_back_max = cfq_back_max;
-	cfqd->cfq_back_penalty = cfq_back_penalty;
-	cfqd->cfq_slice[0] = cfq_slice_async;
-	cfqd->cfq_slice[1] = cfq_slice_sync;
-	cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
-	cfqd->cfq_slice_idle = cfq_slice_idle;
-	cfqd->cfq_max_depth = cfq_max_depth;
-
-	return 0;
-out_crqpool:
-	kfree(cfqd->cfq_hash);
-out_cfqhash:
-	kfree(cfqd->crq_hash);
-out_crqhash:
-	kfree(cfqd);
-	return -ENOMEM;
-}
-
-static void cfq_slab_kill(void)
-{
-	if (crq_pool)
-		kmem_cache_destroy(crq_pool);
-	if (cfq_pool)
-		kmem_cache_destroy(cfq_pool);
-	if (cfq_ioc_pool)
-		kmem_cache_destroy(cfq_ioc_pool);
-}
-
-static int __init cfq_slab_setup(void)
-{
-	crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0,
-					NULL, NULL);
-	if (!crq_pool)
-		goto fail;
-
-	cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0,
-					NULL, NULL);
-	if (!cfq_pool)
-		goto fail;
-
-	cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool",
-			sizeof(struct cfq_io_context), 0, 0, NULL, NULL);
-	if (!cfq_ioc_pool)
-		goto fail;
-
-	return 0;
-fail:
-	cfq_slab_kill();
-	return -ENOMEM;
-}
-
-/*
- * sysfs parts below -->
- */
-struct cfq_fs_entry {
-	struct attribute attr;
-	ssize_t (*show)(struct cfq_data *, char *);
-	ssize_t (*store)(struct cfq_data *, const char *, size_t);
-};
-
-static ssize_t
-cfq_var_show(unsigned int var, char *page)
-{
-	return sprintf(page, "%d\n", var);
-}
-
-static ssize_t
-cfq_var_store(unsigned int *var, const char *page, size_t count)
-{
-	char *p = (char *) page;
-
-	*var = simple_strtoul(p, &p, 10);
-	return count;
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
-static ssize_t __FUNC(struct cfq_data *cfqd, char *page)		\
-{									\
-	unsigned int __data = __VAR;					\
-	if (__CONV)							\
-		__data = jiffies_to_msecs(__data);			\
-	return cfq_var_show(__data, (page));				\
-}
-SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
-SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0);
-SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
-SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
-SHOW_FUNCTION(cfq_back_max_show, cfqd->cfq_back_max, 0);
-SHOW_FUNCTION(cfq_back_penalty_show, cfqd->cfq_back_penalty, 0);
-SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
-SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
-SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
-SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
-SHOW_FUNCTION(cfq_max_depth_show, cfqd->cfq_max_depth, 0);
-#undef SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
-static ssize_t __FUNC(struct cfq_data *cfqd, const char *page, size_t count)	\
-{									\
-	unsigned int __data;						\
-	int ret = cfq_var_store(&__data, (page), count);		\
-	if (__data < (MIN))						\
-		__data = (MIN);						\
-	else if (__data > (MAX))					\
-		__data = (MAX);						\
-	if (__CONV)							\
-		*(__PTR) = msecs_to_jiffies(__data);			\
-	else								\
-		*(__PTR) = __data;					\
-	return ret;							\
-}
-STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_back_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
-STORE_FUNCTION(cfq_back_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_max_depth_store, &cfqd->cfq_max_depth, 1, UINT_MAX, 0);
-#undef STORE_FUNCTION
-
-static struct cfq_fs_entry cfq_quantum_entry = {
-	.attr = {.name = "quantum", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_quantum_show,
-	.store = cfq_quantum_store,
-};
-static struct cfq_fs_entry cfq_queued_entry = {
-	.attr = {.name = "queued", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_queued_show,
-	.store = cfq_queued_store,
-};
-static struct cfq_fs_entry cfq_fifo_expire_sync_entry = {
-	.attr = {.name = "fifo_expire_sync", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_fifo_expire_sync_show,
-	.store = cfq_fifo_expire_sync_store,
-};
-static struct cfq_fs_entry cfq_fifo_expire_async_entry = {
-	.attr = {.name = "fifo_expire_async", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_fifo_expire_async_show,
-	.store = cfq_fifo_expire_async_store,
-};
-static struct cfq_fs_entry cfq_back_max_entry = {
-	.attr = {.name = "back_seek_max", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_back_max_show,
-	.store = cfq_back_max_store,
-};
-static struct cfq_fs_entry cfq_back_penalty_entry = {
-	.attr = {.name = "back_seek_penalty", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_back_penalty_show,
-	.store = cfq_back_penalty_store,
-};
-static struct cfq_fs_entry cfq_slice_sync_entry = {
-	.attr = {.name = "slice_sync", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_sync_show,
-	.store = cfq_slice_sync_store,
-};
-static struct cfq_fs_entry cfq_slice_async_entry = {
-	.attr = {.name = "slice_async", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_async_show,
-	.store = cfq_slice_async_store,
-};
-static struct cfq_fs_entry cfq_slice_async_rq_entry = {
-	.attr = {.name = "slice_async_rq", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_async_rq_show,
-	.store = cfq_slice_async_rq_store,
-};
-static struct cfq_fs_entry cfq_slice_idle_entry = {
-	.attr = {.name = "slice_idle", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_slice_idle_show,
-	.store = cfq_slice_idle_store,
-};
-static struct cfq_fs_entry cfq_max_depth_entry = {
-	.attr = {.name = "max_depth", .mode = S_IRUGO | S_IWUSR },
-	.show = cfq_max_depth_show,
-	.store = cfq_max_depth_store,
-};
-
-static struct attribute *default_attrs[] = {
-	&cfq_quantum_entry.attr,
-	&cfq_queued_entry.attr,
-	&cfq_fifo_expire_sync_entry.attr,
-	&cfq_fifo_expire_async_entry.attr,
-	&cfq_back_max_entry.attr,
-	&cfq_back_penalty_entry.attr,
-	&cfq_slice_sync_entry.attr,
-	&cfq_slice_async_entry.attr,
-	&cfq_slice_async_rq_entry.attr,
-	&cfq_slice_idle_entry.attr,
-	&cfq_max_depth_entry.attr,
-	NULL,
-};
-
-#define to_cfq(atr) container_of((atr), struct cfq_fs_entry, attr)
-
-static ssize_t
-cfq_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct cfq_fs_entry *entry = to_cfq(attr);
-
-	if (!entry->show)
-		return -EIO;
-
-	return entry->show(e->elevator_data, page);
-}
-
-static ssize_t
-cfq_attr_store(struct kobject *kobj, struct attribute *attr,
-	       const char *page, size_t length)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct cfq_fs_entry *entry = to_cfq(attr);
-
-	if (!entry->store)
-		return -EIO;
-
-	return entry->store(e->elevator_data, page, length);
-}
-
-static struct sysfs_ops cfq_sysfs_ops = {
-	.show	= cfq_attr_show,
-	.store	= cfq_attr_store,
-};
-
-static struct kobj_type cfq_ktype = {
-	.sysfs_ops	= &cfq_sysfs_ops,
-	.default_attrs	= default_attrs,
-};
-
-static struct elevator_type iosched_cfq = {
-	.ops = {
-		.elevator_merge_fn = 		cfq_merge,
-		.elevator_merged_fn =		cfq_merged_request,
-		.elevator_merge_req_fn =	cfq_merged_requests,
-		.elevator_dispatch_fn =		cfq_dispatch_requests,
-		.elevator_add_req_fn =		cfq_insert_request,
-		.elevator_activate_req_fn =	cfq_activate_request,
-		.elevator_deactivate_req_fn =	cfq_deactivate_request,
-		.elevator_queue_empty_fn =	cfq_queue_empty,
-		.elevator_completed_req_fn =	cfq_completed_request,
-		.elevator_former_req_fn =	cfq_former_request,
-		.elevator_latter_req_fn =	cfq_latter_request,
-		.elevator_set_req_fn =		cfq_set_request,
-		.elevator_put_req_fn =		cfq_put_request,
-		.elevator_may_queue_fn =	cfq_may_queue,
-		.elevator_init_fn =		cfq_init_queue,
-		.elevator_exit_fn =		cfq_exit_queue,
-	},
-	.elevator_ktype =	&cfq_ktype,
-	.elevator_name =	"cfq",
-	.elevator_owner =	THIS_MODULE,
-};
-
-static int __init cfq_init(void)
-{
-	int ret;
-
-	/*
-	 * could be 0 on HZ < 1000 setups
-	 */
-	if (!cfq_slice_async)
-		cfq_slice_async = 1;
-	if (!cfq_slice_idle)
-		cfq_slice_idle = 1;
-
-	if (cfq_slab_setup())
-		return -ENOMEM;
-
-	ret = elv_register(&iosched_cfq);
-	if (ret)
-		cfq_slab_kill();
-
-	return ret;
-}
-
-static void __exit cfq_exit(void)
-{
-	elv_unregister(&iosched_cfq);
-	cfq_slab_kill();
-}
-
-module_init(cfq_init);
-module_exit(cfq_exit);
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");
diff --git a/drivers/block/deadline-iosched.c b/drivers/block/deadline-iosched.c
deleted file mode 100644
index 7929471d7df7..000000000000
--- a/drivers/block/deadline-iosched.c
+++ /dev/null
@@ -1,878 +0,0 @@
-/*
- *  linux/drivers/block/deadline-iosched.c
- *
- *  Deadline i/o scheduler.
- *
- *  Copyright (C) 2002 Jens Axboe <axboe@suse.de>
- */
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/config.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/hash.h>
-#include <linux/rbtree.h>
-
-/*
- * See Documentation/block/deadline-iosched.txt
- */
-static int read_expire = HZ / 2;  /* max time before a read is submitted. */
-static int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
-static int writes_starved = 2;    /* max times reads can starve a write */
-static int fifo_batch = 16;       /* # of sequential requests treated as one
-				     by the above parameters. For throughput. */
-
-static const int deadline_hash_shift = 5;
-#define DL_HASH_BLOCK(sec)	((sec) >> 3)
-#define DL_HASH_FN(sec)		(hash_long(DL_HASH_BLOCK((sec)), deadline_hash_shift))
-#define DL_HASH_ENTRIES		(1 << deadline_hash_shift)
-#define rq_hash_key(rq)		((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr)	list_entry((ptr), struct deadline_rq, hash)
-#define ON_HASH(drq)		(drq)->on_hash
-
-struct deadline_data {
-	/*
-	 * run time data
-	 */
-
-	/*
-	 * requests (deadline_rq s) are present on both sort_list and fifo_list
-	 */
-	struct rb_root sort_list[2];	
-	struct list_head fifo_list[2];
-	
-	/*
-	 * next in sort order. read, write or both are NULL
-	 */
-	struct deadline_rq *next_drq[2];
-	struct list_head *hash;		/* request hash */
-	unsigned int batching;		/* number of sequential requests made */
-	sector_t last_sector;		/* head position */
-	unsigned int starved;		/* times reads have starved writes */
-
-	/*
-	 * settings that change how the i/o scheduler behaves
-	 */
-	int fifo_expire[2];
-	int fifo_batch;
-	int writes_starved;
-	int front_merges;
-
-	mempool_t *drq_pool;
-};
-
-/*
- * pre-request data.
- */
-struct deadline_rq {
-	/*
-	 * rbtree index, key is the starting offset
-	 */
-	struct rb_node rb_node;
-	sector_t rb_key;
-
-	struct request *request;
-
-	/*
-	 * request hash, key is the ending offset (for back merge lookup)
-	 */
-	struct list_head hash;
-	char on_hash;
-
-	/*
-	 * expire fifo
-	 */
-	struct list_head fifo;
-	unsigned long expires;
-};
-
-static void deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq);
-
-static kmem_cache_t *drq_pool;
-
-#define RQ_DATA(rq)	((struct deadline_rq *) (rq)->elevator_private)
-
-/*
- * the back merge hash support functions
- */
-static inline void __deadline_del_drq_hash(struct deadline_rq *drq)
-{
-	drq->on_hash = 0;
-	list_del_init(&drq->hash);
-}
-
-static inline void deadline_del_drq_hash(struct deadline_rq *drq)
-{
-	if (ON_HASH(drq))
-		__deadline_del_drq_hash(drq);
-}
-
-static inline void
-deadline_add_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
-{
-	struct request *rq = drq->request;
-
-	BUG_ON(ON_HASH(drq));
-
-	drq->on_hash = 1;
-	list_add(&drq->hash, &dd->hash[DL_HASH_FN(rq_hash_key(rq))]);
-}
-
-/*
- * move hot entry to front of chain
- */
-static inline void
-deadline_hot_drq_hash(struct deadline_data *dd, struct deadline_rq *drq)
-{
-	struct request *rq = drq->request;
-	struct list_head *head = &dd->hash[DL_HASH_FN(rq_hash_key(rq))];
-
-	if (ON_HASH(drq) && drq->hash.prev != head) {
-		list_del(&drq->hash);
-		list_add(&drq->hash, head);
-	}
-}
-
-static struct request *
-deadline_find_drq_hash(struct deadline_data *dd, sector_t offset)
-{
-	struct list_head *hash_list = &dd->hash[DL_HASH_FN(offset)];
-	struct list_head *entry, *next = hash_list->next;
-
-	while ((entry = next) != hash_list) {
-		struct deadline_rq *drq = list_entry_hash(entry);
-		struct request *__rq = drq->request;
-
-		next = entry->next;
-		
-		BUG_ON(!ON_HASH(drq));
-
-		if (!rq_mergeable(__rq)) {
-			__deadline_del_drq_hash(drq);
-			continue;
-		}
-
-		if (rq_hash_key(__rq) == offset)
-			return __rq;
-	}
-
-	return NULL;
-}
-
-/*
- * rb tree support functions
- */
-#define RB_NONE		(2)
-#define RB_EMPTY(root)	((root)->rb_node == NULL)
-#define ON_RB(node)	((node)->rb_color != RB_NONE)
-#define RB_CLEAR(node)	((node)->rb_color = RB_NONE)
-#define rb_entry_drq(node)	rb_entry((node), struct deadline_rq, rb_node)
-#define DRQ_RB_ROOT(dd, drq)	(&(dd)->sort_list[rq_data_dir((drq)->request)])
-#define rq_rb_key(rq)		(rq)->sector
-
-static struct deadline_rq *
-__deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
-{
-	struct rb_node **p = &DRQ_RB_ROOT(dd, drq)->rb_node;
-	struct rb_node *parent = NULL;
-	struct deadline_rq *__drq;
-
-	while (*p) {
-		parent = *p;
-		__drq = rb_entry_drq(parent);
-
-		if (drq->rb_key < __drq->rb_key)
-			p = &(*p)->rb_left;
-		else if (drq->rb_key > __drq->rb_key)
-			p = &(*p)->rb_right;
-		else
-			return __drq;
-	}
-
-	rb_link_node(&drq->rb_node, parent, p);
-	return NULL;
-}
-
-static void
-deadline_add_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
-{
-	struct deadline_rq *__alias;
-
-	drq->rb_key = rq_rb_key(drq->request);
-
-retry:
-	__alias = __deadline_add_drq_rb(dd, drq);
-	if (!__alias) {
-		rb_insert_color(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
-		return;
-	}
-
-	deadline_move_request(dd, __alias);
-	goto retry;
-}
-
-static inline void
-deadline_del_drq_rb(struct deadline_data *dd, struct deadline_rq *drq)
-{
-	const int data_dir = rq_data_dir(drq->request);
-
-	if (dd->next_drq[data_dir] == drq) {
-		struct rb_node *rbnext = rb_next(&drq->rb_node);
-
-		dd->next_drq[data_dir] = NULL;
-		if (rbnext)
-			dd->next_drq[data_dir] = rb_entry_drq(rbnext);
-	}
-
-	BUG_ON(!ON_RB(&drq->rb_node));
-	rb_erase(&drq->rb_node, DRQ_RB_ROOT(dd, drq));
-	RB_CLEAR(&drq->rb_node);
-}
-
-static struct request *
-deadline_find_drq_rb(struct deadline_data *dd, sector_t sector, int data_dir)
-{
-	struct rb_node *n = dd->sort_list[data_dir].rb_node;
-	struct deadline_rq *drq;
-
-	while (n) {
-		drq = rb_entry_drq(n);
-
-		if (sector < drq->rb_key)
-			n = n->rb_left;
-		else if (sector > drq->rb_key)
-			n = n->rb_right;
-		else
-			return drq->request;
-	}
-
-	return NULL;
-}
-
-/*
- * deadline_find_first_drq finds the first (lowest sector numbered) request
- * for the specified data_dir. Used to sweep back to the start of the disk
- * (1-way elevator) after we process the last (highest sector) request.
- */
-static struct deadline_rq *
-deadline_find_first_drq(struct deadline_data *dd, int data_dir)
-{
-	struct rb_node *n = dd->sort_list[data_dir].rb_node;
-
-	for (;;) {
-		if (n->rb_left == NULL)
-			return rb_entry_drq(n);
-		
-		n = n->rb_left;
-	}
-}
-
-/*
- * add drq to rbtree and fifo
- */
-static void
-deadline_add_request(struct request_queue *q, struct request *rq)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	struct deadline_rq *drq = RQ_DATA(rq);
-
-	const int data_dir = rq_data_dir(drq->request);
-
-	deadline_add_drq_rb(dd, drq);
-	/*
-	 * set expire time (only used for reads) and add to fifo list
-	 */
-	drq->expires = jiffies + dd->fifo_expire[data_dir];
-	list_add_tail(&drq->fifo, &dd->fifo_list[data_dir]);
-
-	if (rq_mergeable(rq))
-		deadline_add_drq_hash(dd, drq);
-}
-
-/*
- * remove rq from rbtree, fifo, and hash
- */
-static void deadline_remove_request(request_queue_t *q, struct request *rq)
-{
-	struct deadline_rq *drq = RQ_DATA(rq);
-	struct deadline_data *dd = q->elevator->elevator_data;
-
-	list_del_init(&drq->fifo);
-	deadline_del_drq_rb(dd, drq);
-	deadline_del_drq_hash(drq);
-}
-
-static int
-deadline_merge(request_queue_t *q, struct request **req, struct bio *bio)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	struct request *__rq;
-	int ret;
-
-	/*
-	 * see if the merge hash can satisfy a back merge
-	 */
-	__rq = deadline_find_drq_hash(dd, bio->bi_sector);
-	if (__rq) {
-		BUG_ON(__rq->sector + __rq->nr_sectors != bio->bi_sector);
-
-		if (elv_rq_merge_ok(__rq, bio)) {
-			ret = ELEVATOR_BACK_MERGE;
-			goto out;
-		}
-	}
-
-	/*
-	 * check for front merge
-	 */
-	if (dd->front_merges) {
-		sector_t rb_key = bio->bi_sector + bio_sectors(bio);
-
-		__rq = deadline_find_drq_rb(dd, rb_key, bio_data_dir(bio));
-		if (__rq) {
-			BUG_ON(rb_key != rq_rb_key(__rq));
-
-			if (elv_rq_merge_ok(__rq, bio)) {
-				ret = ELEVATOR_FRONT_MERGE;
-				goto out;
-			}
-		}
-	}
-
-	return ELEVATOR_NO_MERGE;
-out:
-	if (ret)
-		deadline_hot_drq_hash(dd, RQ_DATA(__rq));
-	*req = __rq;
-	return ret;
-}
-
-static void deadline_merged_request(request_queue_t *q, struct request *req)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	struct deadline_rq *drq = RQ_DATA(req);
-
-	/*
-	 * hash always needs to be repositioned, key is end sector
-	 */
-	deadline_del_drq_hash(drq);
-	deadline_add_drq_hash(dd, drq);
-
-	/*
-	 * if the merge was a front merge, we need to reposition request
-	 */
-	if (rq_rb_key(req) != drq->rb_key) {
-		deadline_del_drq_rb(dd, drq);
-		deadline_add_drq_rb(dd, drq);
-	}
-}
-
-static void
-deadline_merged_requests(request_queue_t *q, struct request *req,
-			 struct request *next)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	struct deadline_rq *drq = RQ_DATA(req);
-	struct deadline_rq *dnext = RQ_DATA(next);
-
-	BUG_ON(!drq);
-	BUG_ON(!dnext);
-
-	/*
-	 * reposition drq (this is the merged request) in hash, and in rbtree
-	 * in case of a front merge
-	 */
-	deadline_del_drq_hash(drq);
-	deadline_add_drq_hash(dd, drq);
-
-	if (rq_rb_key(req) != drq->rb_key) {
-		deadline_del_drq_rb(dd, drq);
-		deadline_add_drq_rb(dd, drq);
-	}
-
-	/*
-	 * if dnext expires before drq, assign its expire time to drq
-	 * and move into dnext position (dnext will be deleted) in fifo
-	 */
-	if (!list_empty(&drq->fifo) && !list_empty(&dnext->fifo)) {
-		if (time_before(dnext->expires, drq->expires)) {
-			list_move(&drq->fifo, &dnext->fifo);
-			drq->expires = dnext->expires;
-		}
-	}
-
-	/*
-	 * kill knowledge of next, this one is a goner
-	 */
-	deadline_remove_request(q, next);
-}
-
-/*
- * move request from sort list to dispatch queue.
- */
-static inline void
-deadline_move_to_dispatch(struct deadline_data *dd, struct deadline_rq *drq)
-{
-	request_queue_t *q = drq->request->q;
-
-	deadline_remove_request(q, drq->request);
-	elv_dispatch_add_tail(q, drq->request);
-}
-
-/*
- * move an entry to dispatch queue
- */
-static void
-deadline_move_request(struct deadline_data *dd, struct deadline_rq *drq)
-{
-	const int data_dir = rq_data_dir(drq->request);
-	struct rb_node *rbnext = rb_next(&drq->rb_node);
-
-	dd->next_drq[READ] = NULL;
-	dd->next_drq[WRITE] = NULL;
-
-	if (rbnext)
-		dd->next_drq[data_dir] = rb_entry_drq(rbnext);
-	
-	dd->last_sector = drq->request->sector + drq->request->nr_sectors;
-
-	/*
-	 * take it off the sort and fifo list, move
-	 * to dispatch queue
-	 */
-	deadline_move_to_dispatch(dd, drq);
-}
-
-#define list_entry_fifo(ptr)	list_entry((ptr), struct deadline_rq, fifo)
-
-/*
- * deadline_check_fifo returns 0 if there are no expired reads on the fifo,
- * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
- */
-static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
-{
-	struct deadline_rq *drq = list_entry_fifo(dd->fifo_list[ddir].next);
-
-	/*
-	 * drq is expired!
-	 */
-	if (time_after(jiffies, drq->expires))
-		return 1;
-
-	return 0;
-}
-
-/*
- * deadline_dispatch_requests selects the best request according to
- * read/write expire, fifo_batch, etc
- */
-static int deadline_dispatch_requests(request_queue_t *q, int force)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	const int reads = !list_empty(&dd->fifo_list[READ]);
-	const int writes = !list_empty(&dd->fifo_list[WRITE]);
-	struct deadline_rq *drq;
-	int data_dir;
-
-	/*
-	 * batches are currently reads XOR writes
-	 */
-	if (dd->next_drq[WRITE])
-		drq = dd->next_drq[WRITE];
-	else
-		drq = dd->next_drq[READ];
-
-	if (drq) {
-		/* we have a "next request" */
-		
-		if (dd->last_sector != drq->request->sector)
-			/* end the batch on a non sequential request */
-			dd->batching += dd->fifo_batch;
-		
-		if (dd->batching < dd->fifo_batch)
-			/* we are still entitled to batch */
-			goto dispatch_request;
-	}
-
-	/*
-	 * at this point we are not running a batch. select the appropriate
-	 * data direction (read / write)
-	 */
-
-	if (reads) {
-		BUG_ON(RB_EMPTY(&dd->sort_list[READ]));
-
-		if (writes && (dd->starved++ >= dd->writes_starved))
-			goto dispatch_writes;
-
-		data_dir = READ;
-
-		goto dispatch_find_request;
-	}
-
-	/*
-	 * there are either no reads or writes have been starved
-	 */
-
-	if (writes) {
-dispatch_writes:
-		BUG_ON(RB_EMPTY(&dd->sort_list[WRITE]));
-
-		dd->starved = 0;
-
-		data_dir = WRITE;
-
-		goto dispatch_find_request;
-	}
-
-	return 0;
-
-dispatch_find_request:
-	/*
-	 * we are not running a batch, find best request for selected data_dir
-	 */
-	if (deadline_check_fifo(dd, data_dir)) {
-		/* An expired request exists - satisfy it */
-		dd->batching = 0;
-		drq = list_entry_fifo(dd->fifo_list[data_dir].next);
-		
-	} else if (dd->next_drq[data_dir]) {
-		/*
-		 * The last req was the same dir and we have a next request in
-		 * sort order. No expired requests so continue on from here.
-		 */
-		drq = dd->next_drq[data_dir];
-	} else {
-		/*
-		 * The last req was the other direction or we have run out of
-		 * higher-sectored requests. Go back to the lowest sectored
-		 * request (1 way elevator) and start a new batch.
-		 */
-		dd->batching = 0;
-		drq = deadline_find_first_drq(dd, data_dir);
-	}
-
-dispatch_request:
-	/*
-	 * drq is the selected appropriate request.
-	 */
-	dd->batching++;
-	deadline_move_request(dd, drq);
-
-	return 1;
-}
-
-static int deadline_queue_empty(request_queue_t *q)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-
-	return list_empty(&dd->fifo_list[WRITE])
-		&& list_empty(&dd->fifo_list[READ]);
-}
-
-static struct request *
-deadline_former_request(request_queue_t *q, struct request *rq)
-{
-	struct deadline_rq *drq = RQ_DATA(rq);
-	struct rb_node *rbprev = rb_prev(&drq->rb_node);
-
-	if (rbprev)
-		return rb_entry_drq(rbprev)->request;
-
-	return NULL;
-}
-
-static struct request *
-deadline_latter_request(request_queue_t *q, struct request *rq)
-{
-	struct deadline_rq *drq = RQ_DATA(rq);
-	struct rb_node *rbnext = rb_next(&drq->rb_node);
-
-	if (rbnext)
-		return rb_entry_drq(rbnext)->request;
-
-	return NULL;
-}
-
-static void deadline_exit_queue(elevator_t *e)
-{
-	struct deadline_data *dd = e->elevator_data;
-
-	BUG_ON(!list_empty(&dd->fifo_list[READ]));
-	BUG_ON(!list_empty(&dd->fifo_list[WRITE]));
-
-	mempool_destroy(dd->drq_pool);
-	kfree(dd->hash);
-	kfree(dd);
-}
-
-/*
- * initialize elevator private data (deadline_data), and alloc a drq for
- * each request on the free lists
- */
-static int deadline_init_queue(request_queue_t *q, elevator_t *e)
-{
-	struct deadline_data *dd;
-	int i;
-
-	if (!drq_pool)
-		return -ENOMEM;
-
-	dd = kmalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
-	if (!dd)
-		return -ENOMEM;
-	memset(dd, 0, sizeof(*dd));
-
-	dd->hash = kmalloc_node(sizeof(struct list_head)*DL_HASH_ENTRIES,
-				GFP_KERNEL, q->node);
-	if (!dd->hash) {
-		kfree(dd);
-		return -ENOMEM;
-	}
-
-	dd->drq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
-					mempool_free_slab, drq_pool, q->node);
-	if (!dd->drq_pool) {
-		kfree(dd->hash);
-		kfree(dd);
-		return -ENOMEM;
-	}
-
-	for (i = 0; i < DL_HASH_ENTRIES; i++)
-		INIT_LIST_HEAD(&dd->hash[i]);
-
-	INIT_LIST_HEAD(&dd->fifo_list[READ]);
-	INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
-	dd->sort_list[READ] = RB_ROOT;
-	dd->sort_list[WRITE] = RB_ROOT;
-	dd->fifo_expire[READ] = read_expire;
-	dd->fifo_expire[WRITE] = write_expire;
-	dd->writes_starved = writes_starved;
-	dd->front_merges = 1;
-	dd->fifo_batch = fifo_batch;
-	e->elevator_data = dd;
-	return 0;
-}
-
-static void deadline_put_request(request_queue_t *q, struct request *rq)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	struct deadline_rq *drq = RQ_DATA(rq);
-
-	mempool_free(drq, dd->drq_pool);
-	rq->elevator_private = NULL;
-}
-
-static int
-deadline_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
-		     gfp_t gfp_mask)
-{
-	struct deadline_data *dd = q->elevator->elevator_data;
-	struct deadline_rq *drq;
-
-	drq = mempool_alloc(dd->drq_pool, gfp_mask);
-	if (drq) {
-		memset(drq, 0, sizeof(*drq));
-		RB_CLEAR(&drq->rb_node);
-		drq->request = rq;
-
-		INIT_LIST_HEAD(&drq->hash);
-		drq->on_hash = 0;
-
-		INIT_LIST_HEAD(&drq->fifo);
-
-		rq->elevator_private = drq;
-		return 0;
-	}
-
-	return 1;
-}
-
-/*
- * sysfs parts below
- */
-struct deadline_fs_entry {
-	struct attribute attr;
-	ssize_t (*show)(struct deadline_data *, char *);
-	ssize_t (*store)(struct deadline_data *, const char *, size_t);
-};
-
-static ssize_t
-deadline_var_show(int var, char *page)
-{
-	return sprintf(page, "%d\n", var);
-}
-
-static ssize_t
-deadline_var_store(int *var, const char *page, size_t count)
-{
-	char *p = (char *) page;
-
-	*var = simple_strtol(p, &p, 10);
-	return count;
-}
-
-#define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
-static ssize_t __FUNC(struct deadline_data *dd, char *page)		\
-{									\
-	int __data = __VAR;					\
-	if (__CONV)							\
-		__data = jiffies_to_msecs(__data);			\
-	return deadline_var_show(__data, (page));			\
-}
-SHOW_FUNCTION(deadline_readexpire_show, dd->fifo_expire[READ], 1);
-SHOW_FUNCTION(deadline_writeexpire_show, dd->fifo_expire[WRITE], 1);
-SHOW_FUNCTION(deadline_writesstarved_show, dd->writes_starved, 0);
-SHOW_FUNCTION(deadline_frontmerges_show, dd->front_merges, 0);
-SHOW_FUNCTION(deadline_fifobatch_show, dd->fifo_batch, 0);
-#undef SHOW_FUNCTION
-
-#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
-static ssize_t __FUNC(struct deadline_data *dd, const char *page, size_t count)	\
-{									\
-	int __data;							\
-	int ret = deadline_var_store(&__data, (page), count);		\
-	if (__data < (MIN))						\
-		__data = (MIN);						\
-	else if (__data > (MAX))					\
-		__data = (MAX);						\
-	if (__CONV)							\
-		*(__PTR) = msecs_to_jiffies(__data);			\
-	else								\
-		*(__PTR) = __data;					\
-	return ret;							\
-}
-STORE_FUNCTION(deadline_readexpire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1);
-STORE_FUNCTION(deadline_writeexpire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1);
-STORE_FUNCTION(deadline_writesstarved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0);
-STORE_FUNCTION(deadline_frontmerges_store, &dd->front_merges, 0, 1, 0);
-STORE_FUNCTION(deadline_fifobatch_store, &dd->fifo_batch, 0, INT_MAX, 0);
-#undef STORE_FUNCTION
-
-static struct deadline_fs_entry deadline_readexpire_entry = {
-	.attr = {.name = "read_expire", .mode = S_IRUGO | S_IWUSR },
-	.show = deadline_readexpire_show,
-	.store = deadline_readexpire_store,
-};
-static struct deadline_fs_entry deadline_writeexpire_entry = {
-	.attr = {.name = "write_expire", .mode = S_IRUGO | S_IWUSR },
-	.show = deadline_writeexpire_show,
-	.store = deadline_writeexpire_store,
-};
-static struct deadline_fs_entry deadline_writesstarved_entry = {
-	.attr = {.name = "writes_starved", .mode = S_IRUGO | S_IWUSR },
-	.show = deadline_writesstarved_show,
-	.store = deadline_writesstarved_store,
-};
-static struct deadline_fs_entry deadline_frontmerges_entry = {
-	.attr = {.name = "front_merges", .mode = S_IRUGO | S_IWUSR },
-	.show = deadline_frontmerges_show,
-	.store = deadline_frontmerges_store,
-};
-static struct deadline_fs_entry deadline_fifobatch_entry = {
-	.attr = {.name = "fifo_batch", .mode = S_IRUGO | S_IWUSR },
-	.show = deadline_fifobatch_show,
-	.store = deadline_fifobatch_store,
-};
-
-static struct attribute *default_attrs[] = {
-	&deadline_readexpire_entry.attr,
-	&deadline_writeexpire_entry.attr,
-	&deadline_writesstarved_entry.attr,
-	&deadline_frontmerges_entry.attr,
-	&deadline_fifobatch_entry.attr,
-	NULL,
-};
-
-#define to_deadline(atr) container_of((atr), struct deadline_fs_entry, attr)
-
-static ssize_t
-deadline_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct deadline_fs_entry *entry = to_deadline(attr);
-
-	if (!entry->show)
-		return -EIO;
-
-	return entry->show(e->elevator_data, page);
-}
-
-static ssize_t
-deadline_attr_store(struct kobject *kobj, struct attribute *attr,
-		    const char *page, size_t length)
-{
-	elevator_t *e = container_of(kobj, elevator_t, kobj);
-	struct deadline_fs_entry *entry = to_deadline(attr);
-
-	if (!entry->store)
-		return -EIO;
-
-	return entry->store(e->elevator_data, page, length);
-}
-
-static struct sysfs_ops deadline_sysfs_ops = {
-	.show	= deadline_attr_show,
-	.store	= deadline_attr_store,
-};
-
-static struct kobj_type deadline_ktype = {
-	.sysfs_ops	= &deadline_sysfs_ops,
-	.default_attrs	= default_attrs,
-};
-
-static struct elevator_type iosched_deadline = {
-	.ops = {
-		.elevator_merge_fn = 		deadline_merge,
-		.elevator_merged_fn =		deadline_merged_request,
-		.elevator_merge_req_fn =	deadline_merged_requests,
-		.elevator_dispatch_fn =		deadline_dispatch_requests,
-		.elevator_add_req_fn =		deadline_add_request,
-		.elevator_queue_empty_fn =	deadline_queue_empty,
-		.elevator_former_req_fn =	deadline_former_request,
-		.elevator_latter_req_fn =	deadline_latter_request,
-		.elevator_set_req_fn =		deadline_set_request,
-		.elevator_put_req_fn = 		deadline_put_request,
-		.elevator_init_fn =		deadline_init_queue,
-		.elevator_exit_fn =		deadline_exit_queue,
-	},
-
-	.elevator_ktype = &deadline_ktype,
-	.elevator_name = "deadline",
-	.elevator_owner = THIS_MODULE,
-};
-
-static int __init deadline_init(void)
-{
-	int ret;
-
-	drq_pool = kmem_cache_create("deadline_drq", sizeof(struct deadline_rq),
-				     0, 0, NULL, NULL);
-
-	if (!drq_pool)
-		return -ENOMEM;
-
-	ret = elv_register(&iosched_deadline);
-	if (ret)
-		kmem_cache_destroy(drq_pool);
-
-	return ret;
-}
-
-static void __exit deadline_exit(void)
-{
-	kmem_cache_destroy(drq_pool);
-	elv_unregister(&iosched_deadline);
-}
-
-module_init(deadline_init);
-module_exit(deadline_exit);
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("deadline IO scheduler");
diff --git a/drivers/block/elevator.c b/drivers/block/elevator.c
deleted file mode 100644
index d4a49a3df829..000000000000
--- a/drivers/block/elevator.c
+++ /dev/null
@@ -1,802 +0,0 @@
-/*
- *  linux/drivers/block/elevator.c
- *
- *  Block device elevator/IO-scheduler.
- *
- *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
- *
- * 30042000 Jens Axboe <axboe@suse.de> :
- *
- * Split the elevator a bit so that it is possible to choose a different
- * one or even write a new "plug in". There are three pieces:
- * - elevator_fn, inserts a new request in the queue list
- * - elevator_merge_fn, decides whether a new buffer can be merged with
- *   an existing request
- * - elevator_dequeue_fn, called when a request is taken off the active list
- *
- * 20082000 Dave Jones <davej@suse.de> :
- * Removed tests for max-bomb-segments, which was breaking elvtune
- *  when run without -bN
- *
- * Jens:
- * - Rework again to work with bio instead of buffer_heads
- * - loose bi_dev comparisons, partition handling is right now
- * - completely modularize elevator setup and teardown
- *
- */
-#include <linux/kernel.h>
-#include <linux/fs.h>
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/config.h>
-#include <linux/module.h>
-#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/compiler.h>
-#include <linux/delay.h>
-
-#include <asm/uaccess.h>
-
-static DEFINE_SPINLOCK(elv_list_lock);
-static LIST_HEAD(elv_list);
-
-/*
- * can we safely merge with this request?
- */
-inline int elv_rq_merge_ok(struct request *rq, struct bio *bio)
-{
-	if (!rq_mergeable(rq))
-		return 0;
-
-	/*
-	 * different data direction or already started, don't merge
-	 */
-	if (bio_data_dir(bio) != rq_data_dir(rq))
-		return 0;
-
-	/*
-	 * same device and no special stuff set, merge is ok
-	 */
-	if (rq->rq_disk == bio->bi_bdev->bd_disk &&
-	    !rq->waiting && !rq->special)
-		return 1;
-
-	return 0;
-}
-EXPORT_SYMBOL(elv_rq_merge_ok);
-
-inline int elv_try_merge(struct request *__rq, struct bio *bio)
-{
-	int ret = ELEVATOR_NO_MERGE;
-
-	/*
-	 * we can merge and sequence is ok, check if it's possible
-	 */
-	if (elv_rq_merge_ok(__rq, bio)) {
-		if (__rq->sector + __rq->nr_sectors == bio->bi_sector)
-			ret = ELEVATOR_BACK_MERGE;
-		else if (__rq->sector - bio_sectors(bio) == bio->bi_sector)
-			ret = ELEVATOR_FRONT_MERGE;
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL(elv_try_merge);
-
-static struct elevator_type *elevator_find(const char *name)
-{
-	struct elevator_type *e = NULL;
-	struct list_head *entry;
-
-	list_for_each(entry, &elv_list) {
-		struct elevator_type *__e;
-
-		__e = list_entry(entry, struct elevator_type, list);
-
-		if (!strcmp(__e->elevator_name, name)) {
-			e = __e;
-			break;
-		}
-	}
-
-	return e;
-}
-
-static void elevator_put(struct elevator_type *e)
-{
-	module_put(e->elevator_owner);
-}
-
-static struct elevator_type *elevator_get(const char *name)
-{
-	struct elevator_type *e;
-
-	spin_lock_irq(&elv_list_lock);
-
-	e = elevator_find(name);
-	if (e && !try_module_get(e->elevator_owner))
-		e = NULL;
-
-	spin_unlock_irq(&elv_list_lock);
-
-	return e;
-}
-
-static int elevator_attach(request_queue_t *q, struct elevator_type *e,
-			   struct elevator_queue *eq)
-{
-	int ret = 0;
-
-	memset(eq, 0, sizeof(*eq));
-	eq->ops = &e->ops;
-	eq->elevator_type = e;
-
-	q->elevator = eq;
-
-	if (eq->ops->elevator_init_fn)
-		ret = eq->ops->elevator_init_fn(q, eq);
-
-	return ret;
-}
-
-static char chosen_elevator[16];
-
-static void elevator_setup_default(void)
-{
-	struct elevator_type *e;
-
-	/*
-	 * If default has not been set, use the compiled-in selection.
-	 */
-	if (!chosen_elevator[0])
-		strcpy(chosen_elevator, CONFIG_DEFAULT_IOSCHED);
-
- 	/*
- 	 * If the given scheduler is not available, fall back to no-op.
- 	 */
- 	if (!(e = elevator_find(chosen_elevator)))
- 		strcpy(chosen_elevator, "noop");
-	elevator_put(e);
-}
-
-static int __init elevator_setup(char *str)
-{
-	strncpy(chosen_elevator, str, sizeof(chosen_elevator) - 1);
-	return 0;
-}
-
-__setup("elevator=", elevator_setup);
-
-int elevator_init(request_queue_t *q, char *name)
-{
-	struct elevator_type *e = NULL;
-	struct elevator_queue *eq;
-	int ret = 0;
-
-	INIT_LIST_HEAD(&q->queue_head);
-	q->last_merge = NULL;
-	q->end_sector = 0;
-	q->boundary_rq = NULL;
-
-	elevator_setup_default();
-
-	if (!name)
-		name = chosen_elevator;
-
-	e = elevator_get(name);
-	if (!e)
-		return -EINVAL;
-
-	eq = kmalloc(sizeof(struct elevator_queue), GFP_KERNEL);
-	if (!eq) {
-		elevator_put(e->elevator_type);
-		return -ENOMEM;
-	}
-
-	ret = elevator_attach(q, e, eq);
-	if (ret) {
-		kfree(eq);
-		elevator_put(e->elevator_type);
-	}
-
-	return ret;
-}
-
-void elevator_exit(elevator_t *e)
-{
-	if (e->ops->elevator_exit_fn)
-		e->ops->elevator_exit_fn(e);
-
-	elevator_put(e->elevator_type);
-	e->elevator_type = NULL;
-	kfree(e);
-}
-
-/*
- * Insert rq into dispatch queue of q.  Queue lock must be held on
- * entry.  If sort != 0, rq is sort-inserted; otherwise, rq will be
- * appended to the dispatch queue.  To be used by specific elevators.
- */
-void elv_dispatch_sort(request_queue_t *q, struct request *rq)
-{
-	sector_t boundary;
-	struct list_head *entry;
-
-	if (q->last_merge == rq)
-		q->last_merge = NULL;
-
-	boundary = q->end_sector;
-
-	list_for_each_prev(entry, &q->queue_head) {
-		struct request *pos = list_entry_rq(entry);
-
-		if (pos->flags & (REQ_SOFTBARRIER|REQ_HARDBARRIER|REQ_STARTED))
-			break;
-		if (rq->sector >= boundary) {
-			if (pos->sector < boundary)
-				continue;
-		} else {
-			if (pos->sector >= boundary)
-				break;
-		}
-		if (rq->sector >= pos->sector)
-			break;
-	}
-
-	list_add(&rq->queuelist, entry);
-}
-
-int elv_merge(request_queue_t *q, struct request **req, struct bio *bio)
-{
-	elevator_t *e = q->elevator;
-	int ret;
-
-	if (q->last_merge) {
-		ret = elv_try_merge(q->last_merge, bio);
-		if (ret != ELEVATOR_NO_MERGE) {
-			*req = q->last_merge;
-			return ret;
-		}
-	}
-
-	if (e->ops->elevator_merge_fn)
-		return e->ops->elevator_merge_fn(q, req, bio);
-
-	return ELEVATOR_NO_MERGE;
-}
-
-void elv_merged_request(request_queue_t *q, struct request *rq)
-{
-	elevator_t *e = q->elevator;
-
-	if (e->ops->elevator_merged_fn)
-		e->ops->elevator_merged_fn(q, rq);
-
-	q->last_merge = rq;
-}
-
-void elv_merge_requests(request_queue_t *q, struct request *rq,
-			     struct request *next)
-{
-	elevator_t *e = q->elevator;
-
-	if (e->ops->elevator_merge_req_fn)
-		e->ops->elevator_merge_req_fn(q, rq, next);
-
-	q->last_merge = rq;
-}
-
-void elv_requeue_request(request_queue_t *q, struct request *rq)
-{
-	elevator_t *e = q->elevator;
-
-	/*
-	 * it already went through dequeue, we need to decrement the
-	 * in_flight count again
-	 */
-	if (blk_account_rq(rq)) {
-		q->in_flight--;
-		if (blk_sorted_rq(rq) && e->ops->elevator_deactivate_req_fn)
-			e->ops->elevator_deactivate_req_fn(q, rq);
-	}
-
-	rq->flags &= ~REQ_STARTED;
-
-	/*
-	 * if this is the flush, requeue the original instead and drop the flush
-	 */
-	if (rq->flags & REQ_BAR_FLUSH) {
-		clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
-		rq = rq->end_io_data;
-	}
-
-	__elv_add_request(q, rq, ELEVATOR_INSERT_FRONT, 0);
-}
-
-void __elv_add_request(request_queue_t *q, struct request *rq, int where,
-		       int plug)
-{
-	if (rq->flags & (REQ_SOFTBARRIER | REQ_HARDBARRIER)) {
-		/*
-		 * barriers implicitly indicate back insertion
-		 */
-		if (where == ELEVATOR_INSERT_SORT)
-			where = ELEVATOR_INSERT_BACK;
-
-		/*
-		 * this request is scheduling boundary, update end_sector
-		 */
-		if (blk_fs_request(rq)) {
-			q->end_sector = rq_end_sector(rq);
-			q->boundary_rq = rq;
-		}
-	} else if (!(rq->flags & REQ_ELVPRIV) && where == ELEVATOR_INSERT_SORT)
-		where = ELEVATOR_INSERT_BACK;
-
-	if (plug)
-		blk_plug_device(q);
-
-	rq->q = q;
-
-	switch (where) {
-	case ELEVATOR_INSERT_FRONT:
-		rq->flags |= REQ_SOFTBARRIER;
-
-		list_add(&rq->queuelist, &q->queue_head);
-		break;
-
-	case ELEVATOR_INSERT_BACK:
-		rq->flags |= REQ_SOFTBARRIER;
-
-		while (q->elevator->ops->elevator_dispatch_fn(q, 1))
-			;
-		list_add_tail(&rq->queuelist, &q->queue_head);
-		/*
-		 * We kick the queue here for the following reasons.
-		 * - The elevator might have returned NULL previously
-		 *   to delay requests and returned them now.  As the
-		 *   queue wasn't empty before this request, ll_rw_blk
-		 *   won't run the queue on return, resulting in hang.
-		 * - Usually, back inserted requests won't be merged
-		 *   with anything.  There's no point in delaying queue
-		 *   processing.
-		 */
-		blk_remove_plug(q);
-		q->request_fn(q);
-		break;
-
-	case ELEVATOR_INSERT_SORT:
-		BUG_ON(!blk_fs_request(rq));
-		rq->flags |= REQ_SORTED;
-		if (q->last_merge == NULL && rq_mergeable(rq))
-			q->last_merge = rq;
-		/*
-		 * Some ioscheds (cfq) run q->request_fn directly, so
-		 * rq cannot be accessed after calling
-		 * elevator_add_req_fn.
-		 */
-		q->elevator->ops->elevator_add_req_fn(q, rq);
-		break;
-
-	default:
-		printk(KERN_ERR "%s: bad insertion point %d\n",
-		       __FUNCTION__, where);
-		BUG();
-	}
-
-	if (blk_queue_plugged(q)) {
-		int nrq = q->rq.count[READ] + q->rq.count[WRITE]
-			- q->in_flight;
-
-		if (nrq >= q->unplug_thresh)
-			__generic_unplug_device(q);
-	}
-}
-
-void elv_add_request(request_queue_t *q, struct request *rq, int where,
-		     int plug)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	__elv_add_request(q, rq, where, plug);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-static inline struct request *__elv_next_request(request_queue_t *q)
-{
-	struct request *rq;
-
-	if (unlikely(list_empty(&q->queue_head) &&
-		     !q->elevator->ops->elevator_dispatch_fn(q, 0)))
-		return NULL;
-
-	rq = list_entry_rq(q->queue_head.next);
-
-	/*
-	 * if this is a barrier write and the device has to issue a
-	 * flush sequence to support it, check how far we are
-	 */
-	if (blk_fs_request(rq) && blk_barrier_rq(rq)) {
-		BUG_ON(q->ordered == QUEUE_ORDERED_NONE);
-
-		if (q->ordered == QUEUE_ORDERED_FLUSH &&
-		    !blk_barrier_preflush(rq))
-			rq = blk_start_pre_flush(q, rq);
-	}
-
-	return rq;
-}
-
-struct request *elv_next_request(request_queue_t *q)
-{
-	struct request *rq;
-	int ret;
-
-	while ((rq = __elv_next_request(q)) != NULL) {
-		if (!(rq->flags & REQ_STARTED)) {
-			elevator_t *e = q->elevator;
-
-			/*
-			 * This is the first time the device driver
-			 * sees this request (possibly after
-			 * requeueing).  Notify IO scheduler.
-			 */
-			if (blk_sorted_rq(rq) &&
-			    e->ops->elevator_activate_req_fn)
-				e->ops->elevator_activate_req_fn(q, rq);
-
-			/*
-			 * just mark as started even if we don't start
-			 * it, a request that has been delayed should
-			 * not be passed by new incoming requests
-			 */
-			rq->flags |= REQ_STARTED;
-		}
-
-		if (!q->boundary_rq || q->boundary_rq == rq) {
-			q->end_sector = rq_end_sector(rq);
-			q->boundary_rq = NULL;
-		}
-
-		if ((rq->flags & REQ_DONTPREP) || !q->prep_rq_fn)
-			break;
-
-		ret = q->prep_rq_fn(q, rq);
-		if (ret == BLKPREP_OK) {
-			break;
-		} else if (ret == BLKPREP_DEFER) {
-			/*
-			 * the request may have been (partially) prepped.
-			 * we need to keep this request in the front to
-			 * avoid resource deadlock.  REQ_STARTED will
-			 * prevent other fs requests from passing this one.
-			 */
-			rq = NULL;
-			break;
-		} else if (ret == BLKPREP_KILL) {
-			int nr_bytes = rq->hard_nr_sectors << 9;
-
-			if (!nr_bytes)
-				nr_bytes = rq->data_len;
-
-			blkdev_dequeue_request(rq);
-			rq->flags |= REQ_QUIET;
-			end_that_request_chunk(rq, 0, nr_bytes);
-			end_that_request_last(rq);
-		} else {
-			printk(KERN_ERR "%s: bad return=%d\n", __FUNCTION__,
-								ret);
-			break;
-		}
-	}
-
-	return rq;
-}
-
-void elv_dequeue_request(request_queue_t *q, struct request *rq)
-{
-	BUG_ON(list_empty(&rq->queuelist));
-
-	list_del_init(&rq->queuelist);
-
-	/*
-	 * the time frame between a request being removed from the lists
-	 * and to it is freed is accounted as io that is in progress at
-	 * the driver side.
-	 */
-	if (blk_account_rq(rq))
-		q->in_flight++;
-}
-
-int elv_queue_empty(request_queue_t *q)
-{
-	elevator_t *e = q->elevator;
-
-	if (!list_empty(&q->queue_head))
-		return 0;
-
-	if (e->ops->elevator_queue_empty_fn)
-		return e->ops->elevator_queue_empty_fn(q);
-
-	return 1;
-}
-
-struct request *elv_latter_request(request_queue_t *q, struct request *rq)
-{
-	struct list_head *next;
-
-	elevator_t *e = q->elevator;
-
-	if (e->ops->elevator_latter_req_fn)
-		return e->ops->elevator_latter_req_fn(q, rq);
-
-	next = rq->queuelist.next;
-	if (next != &q->queue_head && next != &rq->queuelist)
-		return list_entry_rq(next);
-
-	return NULL;
-}
-
-struct request *elv_former_request(request_queue_t *q, struct request *rq)
-{
-	struct list_head *prev;
-
-	elevator_t *e = q->elevator;
-
-	if (e->ops->elevator_former_req_fn)
-		return e->ops->elevator_former_req_fn(q, rq);
-
-	prev = rq->queuelist.prev;
-	if (prev != &q->queue_head && prev != &rq->queuelist)
-		return list_entry_rq(prev);
-
-	return NULL;
-}
-
-int elv_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
-		    gfp_t gfp_mask)
-{
-	elevator_t *e = q->elevator;
-
-	if (e->ops->elevator_set_req_fn)
-		return e->ops->elevator_set_req_fn(q, rq, bio, gfp_mask);
-
-	rq->elevator_private = NULL;
-	return 0;
-}
-
-void elv_put_request(request_queue_t *q, struct request *rq)
-{
-	elevator_t *e = q->elevator;
-
-	if (e->ops->elevator_put_req_fn)
-		e->ops->elevator_put_req_fn(q, rq);
-}
-
-int elv_may_queue(request_queue_t *q, int rw, struct bio *bio)
-{
-	elevator_t *e = q->elevator;
-
-	if (e->ops->elevator_may_queue_fn)
-		return e->ops->elevator_may_queue_fn(q, rw, bio);
-
-	return ELV_MQUEUE_MAY;
-}
-
-void elv_completed_request(request_queue_t *q, struct request *rq)
-{
-	elevator_t *e = q->elevator;
-
-	/*
-	 * request is released from the driver, io must be done
-	 */
-	if (blk_account_rq(rq)) {
-		q->in_flight--;
-		if (blk_sorted_rq(rq) && e->ops->elevator_completed_req_fn)
-			e->ops->elevator_completed_req_fn(q, rq);
-	}
-}
-
-int elv_register_queue(struct request_queue *q)
-{
-	elevator_t *e = q->elevator;
-
-	e->kobj.parent = kobject_get(&q->kobj);
-	if (!e->kobj.parent)
-		return -EBUSY;
-
-	snprintf(e->kobj.name, KOBJ_NAME_LEN, "%s", "iosched");
-	e->kobj.ktype = e->elevator_type->elevator_ktype;
-
-	return kobject_register(&e->kobj);
-}
-
-void elv_unregister_queue(struct request_queue *q)
-{
-	if (q) {
-		elevator_t *e = q->elevator;
-		kobject_unregister(&e->kobj);
-		kobject_put(&q->kobj);
-	}
-}
-
-int elv_register(struct elevator_type *e)
-{
-	spin_lock_irq(&elv_list_lock);
-	if (elevator_find(e->elevator_name))
-		BUG();
-	list_add_tail(&e->list, &elv_list);
-	spin_unlock_irq(&elv_list_lock);
-
-	printk(KERN_INFO "io scheduler %s registered", e->elevator_name);
-	if (!strcmp(e->elevator_name, chosen_elevator))
-		printk(" (default)");
-	printk("\n");
-	return 0;
-}
-EXPORT_SYMBOL_GPL(elv_register);
-
-void elv_unregister(struct elevator_type *e)
-{
-	struct task_struct *g, *p;
-
-	/*
-	 * Iterate every thread in the process to remove the io contexts.
-	 */
-	read_lock(&tasklist_lock);
-	do_each_thread(g, p) {
-		struct io_context *ioc = p->io_context;
-		if (ioc && ioc->cic) {
-			ioc->cic->exit(ioc->cic);
-			ioc->cic->dtor(ioc->cic);
-			ioc->cic = NULL;
-		}
-		if (ioc && ioc->aic) {
-			ioc->aic->exit(ioc->aic);
-			ioc->aic->dtor(ioc->aic);
-			ioc->aic = NULL;
-		}
-	} while_each_thread(g, p);
-	read_unlock(&tasklist_lock);
-
-	spin_lock_irq(&elv_list_lock);
-	list_del_init(&e->list);
-	spin_unlock_irq(&elv_list_lock);
-}
-EXPORT_SYMBOL_GPL(elv_unregister);
-
-/*
- * switch to new_e io scheduler. be careful not to introduce deadlocks -
- * we don't free the old io scheduler, before we have allocated what we
- * need for the new one. this way we have a chance of going back to the old
- * one, if the new one fails init for some reason.
- */
-static void elevator_switch(request_queue_t *q, struct elevator_type *new_e)
-{
-	elevator_t *old_elevator, *e;
-
-	/*
-	 * Allocate new elevator
-	 */
-	e = kmalloc(sizeof(elevator_t), GFP_KERNEL);
-	if (!e)
-		goto error;
-
-	/*
-	 * Turn on BYPASS and drain all requests w/ elevator private data
-	 */
-	spin_lock_irq(q->queue_lock);
-
-	set_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
-
-	while (q->elevator->ops->elevator_dispatch_fn(q, 1))
-		;
-
-	while (q->rq.elvpriv) {
-		spin_unlock_irq(q->queue_lock);
-		msleep(10);
-		spin_lock_irq(q->queue_lock);
-	}
-
-	spin_unlock_irq(q->queue_lock);
-
-	/*
-	 * unregister old elevator data
-	 */
-	elv_unregister_queue(q);
-	old_elevator = q->elevator;
-
-	/*
-	 * attach and start new elevator
-	 */
-	if (elevator_attach(q, new_e, e))
-		goto fail;
-
-	if (elv_register_queue(q))
-		goto fail_register;
-
-	/*
-	 * finally exit old elevator and turn off BYPASS.
-	 */
-	elevator_exit(old_elevator);
-	clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
-	return;
-
-fail_register:
-	/*
-	 * switch failed, exit the new io scheduler and reattach the old
-	 * one again (along with re-adding the sysfs dir)
-	 */
-	elevator_exit(e);
-	e = NULL;
-fail:
-	q->elevator = old_elevator;
-	elv_register_queue(q);
-	clear_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
-	kfree(e);
-error:
-	elevator_put(new_e);
-	printk(KERN_ERR "elevator: switch to %s failed\n",new_e->elevator_name);
-}
-
-ssize_t elv_iosched_store(request_queue_t *q, const char *name, size_t count)
-{
-	char elevator_name[ELV_NAME_MAX];
-	struct elevator_type *e;
-
-	memset(elevator_name, 0, sizeof(elevator_name));
-	strncpy(elevator_name, name, sizeof(elevator_name));
-
-	if (elevator_name[strlen(elevator_name) - 1] == '\n')
-		elevator_name[strlen(elevator_name) - 1] = '\0';
-
-	e = elevator_get(elevator_name);
-	if (!e) {
-		printk(KERN_ERR "elevator: type %s not found\n", elevator_name);
-		return -EINVAL;
-	}
-
-	if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) {
-		elevator_put(e);
-		return count;
-	}
-
-	elevator_switch(q, e);
-	return count;
-}
-
-ssize_t elv_iosched_show(request_queue_t *q, char *name)
-{
-	elevator_t *e = q->elevator;
-	struct elevator_type *elv = e->elevator_type;
-	struct list_head *entry;
-	int len = 0;
-
-	spin_lock_irq(q->queue_lock);
-	list_for_each(entry, &elv_list) {
-		struct elevator_type *__e;
-
-		__e = list_entry(entry, struct elevator_type, list);
-		if (!strcmp(elv->elevator_name, __e->elevator_name))
-			len += sprintf(name+len, "[%s] ", elv->elevator_name);
-		else
-			len += sprintf(name+len, "%s ", __e->elevator_name);
-	}
-	spin_unlock_irq(q->queue_lock);
-
-	len += sprintf(len+name, "\n");
-	return len;
-}
-
-EXPORT_SYMBOL(elv_dispatch_sort);
-EXPORT_SYMBOL(elv_add_request);
-EXPORT_SYMBOL(__elv_add_request);
-EXPORT_SYMBOL(elv_requeue_request);
-EXPORT_SYMBOL(elv_next_request);
-EXPORT_SYMBOL(elv_dequeue_request);
-EXPORT_SYMBOL(elv_queue_empty);
-EXPORT_SYMBOL(elv_completed_request);
-EXPORT_SYMBOL(elevator_exit);
-EXPORT_SYMBOL(elevator_init);
diff --git a/drivers/block/genhd.c b/drivers/block/genhd.c
deleted file mode 100644
index 54aec4a1ae13..000000000000
--- a/drivers/block/genhd.c
+++ /dev/null
@@ -1,726 +0,0 @@
-/*
- *  gendisk handling
- */
-
-#include <linux/config.h>
-#include <linux/module.h>
-#include <linux/fs.h>
-#include <linux/genhd.h>
-#include <linux/kernel.h>
-#include <linux/blkdev.h>
-#include <linux/init.h>
-#include <linux/spinlock.h>
-#include <linux/seq_file.h>
-#include <linux/slab.h>
-#include <linux/kmod.h>
-#include <linux/kobj_map.h>
-#include <linux/buffer_head.h>
-
-#define MAX_PROBE_HASH 255	/* random */
-
-static struct subsystem block_subsys;
-
-static DECLARE_MUTEX(block_subsys_sem);
-
-/*
- * Can be deleted altogether. Later.
- *
- */
-static struct blk_major_name {
-	struct blk_major_name *next;
-	int major;
-	char name[16];
-} *major_names[MAX_PROBE_HASH];
-
-/* index in the above - for now: assume no multimajor ranges */
-static inline int major_to_index(int major)
-{
-	return major % MAX_PROBE_HASH;
-}
-
-#ifdef CONFIG_PROC_FS
-/* get block device names in somewhat random order */
-int get_blkdev_list(char *p, int used)
-{
-	struct blk_major_name *n;
-	int i, len;
-
-	len = snprintf(p, (PAGE_SIZE-used), "\nBlock devices:\n");
-
-	down(&block_subsys_sem);
-	for (i = 0; i < ARRAY_SIZE(major_names); i++) {
-		for (n = major_names[i]; n; n = n->next) {
-			/*
-			 * If the curent string plus the 5 extra characters
-			 * in the line would run us off the page, then we're done
-			 */
-			if ((len + used + strlen(n->name) + 5) >= PAGE_SIZE)
-				goto page_full;
-			len += sprintf(p+len, "%3d %s\n",
-				       n->major, n->name);
-		}
-	}
-page_full:
-	up(&block_subsys_sem);
-
-	return len;
-}
-#endif
-
-int register_blkdev(unsigned int major, const char *name)
-{
-	struct blk_major_name **n, *p;
-	int index, ret = 0;
-
-	down(&block_subsys_sem);
-
-	/* temporary */
-	if (major == 0) {
-		for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
-			if (major_names[index] == NULL)
-				break;
-		}
-
-		if (index == 0) {
-			printk("register_blkdev: failed to get major for %s\n",
-			       name);
-			ret = -EBUSY;
-			goto out;
-		}
-		major = index;
-		ret = major;
-	}
-
-	p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
-	if (p == NULL) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	p->major = major;
-	strlcpy(p->name, name, sizeof(p->name));
-	p->next = NULL;
-	index = major_to_index(major);
-
-	for (n = &major_names[index]; *n; n = &(*n)->next) {
-		if ((*n)->major == major)
-			break;
-	}
-	if (!*n)
-		*n = p;
-	else
-		ret = -EBUSY;
-
-	if (ret < 0) {
-		printk("register_blkdev: cannot get major %d for %s\n",
-		       major, name);
-		kfree(p);
-	}
-out:
-	up(&block_subsys_sem);
-	return ret;
-}
-
-EXPORT_SYMBOL(register_blkdev);
-
-/* todo: make void - error printk here */
-int unregister_blkdev(unsigned int major, const char *name)
-{
-	struct blk_major_name **n;
-	struct blk_major_name *p = NULL;
-	int index = major_to_index(major);
-	int ret = 0;
-
-	down(&block_subsys_sem);
-	for (n = &major_names[index]; *n; n = &(*n)->next)
-		if ((*n)->major == major)
-			break;
-	if (!*n || strcmp((*n)->name, name))
-		ret = -EINVAL;
-	else {
-		p = *n;
-		*n = p->next;
-	}
-	up(&block_subsys_sem);
-	kfree(p);
-
-	return ret;
-}
-
-EXPORT_SYMBOL(unregister_blkdev);
-
-static struct kobj_map *bdev_map;
-
-/*
- * Register device numbers dev..(dev+range-1)
- * range must be nonzero
- * The hash chain is sorted on range, so that subranges can override.
- */
-void blk_register_region(dev_t dev, unsigned long range, struct module *module,
-			 struct kobject *(*probe)(dev_t, int *, void *),
-			 int (*lock)(dev_t, void *), void *data)
-{
-	kobj_map(bdev_map, dev, range, module, probe, lock, data);
-}
-
-EXPORT_SYMBOL(blk_register_region);
-
-void blk_unregister_region(dev_t dev, unsigned long range)
-{
-	kobj_unmap(bdev_map, dev, range);
-}
-
-EXPORT_SYMBOL(blk_unregister_region);
-
-static struct kobject *exact_match(dev_t dev, int *part, void *data)
-{
-	struct gendisk *p = data;
-	return &p->kobj;
-}
-
-static int exact_lock(dev_t dev, void *data)
-{
-	struct gendisk *p = data;
-
-	if (!get_disk(p))
-		return -1;
-	return 0;
-}
-
-/**
- * add_disk - add partitioning information to kernel list
- * @disk: per-device partitioning information
- *
- * This function registers the partitioning information in @disk
- * with the kernel.
- */
-void add_disk(struct gendisk *disk)
-{
-	disk->flags |= GENHD_FL_UP;
-	blk_register_region(MKDEV(disk->major, disk->first_minor),
-			    disk->minors, NULL, exact_match, exact_lock, disk);
-	register_disk(disk);
-	blk_register_queue(disk);
-}
-
-EXPORT_SYMBOL(add_disk);
-EXPORT_SYMBOL(del_gendisk);	/* in partitions/check.c */
-
-void unlink_gendisk(struct gendisk *disk)
-{
-	blk_unregister_queue(disk);
-	blk_unregister_region(MKDEV(disk->major, disk->first_minor),
-			      disk->minors);
-}
-
-#define to_disk(obj) container_of(obj,struct gendisk,kobj)
-
-/**
- * get_gendisk - get partitioning information for a given device
- * @dev: device to get partitioning information for
- *
- * This function gets the structure containing partitioning
- * information for the given device @dev.
- */
-struct gendisk *get_gendisk(dev_t dev, int *part)
-{
-	struct kobject *kobj = kobj_lookup(bdev_map, dev, part);
-	return  kobj ? to_disk(kobj) : NULL;
-}
-
-#ifdef CONFIG_PROC_FS
-/* iterator */
-static void *part_start(struct seq_file *part, loff_t *pos)
-{
-	struct list_head *p;
-	loff_t l = *pos;
-
-	down(&block_subsys_sem);
-	list_for_each(p, &block_subsys.kset.list)
-		if (!l--)
-			return list_entry(p, struct gendisk, kobj.entry);
-	return NULL;
-}
-
-static void *part_next(struct seq_file *part, void *v, loff_t *pos)
-{
-	struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
-	++*pos;
-	return p==&block_subsys.kset.list ? NULL : 
-		list_entry(p, struct gendisk, kobj.entry);
-}
-
-static void part_stop(struct seq_file *part, void *v)
-{
-	up(&block_subsys_sem);
-}
-
-static int show_partition(struct seq_file *part, void *v)
-{
-	struct gendisk *sgp = v;
-	int n;
-	char buf[BDEVNAME_SIZE];
-
-	if (&sgp->kobj.entry == block_subsys.kset.list.next)
-		seq_puts(part, "major minor  #blocks  name\n\n");
-
-	/* Don't show non-partitionable removeable devices or empty devices */
-	if (!get_capacity(sgp) ||
-			(sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
-		return 0;
-	if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
-		return 0;
-
-	/* show the full disk and all non-0 size partitions of it */
-	seq_printf(part, "%4d  %4d %10llu %s\n",
-		sgp->major, sgp->first_minor,
-		(unsigned long long)get_capacity(sgp) >> 1,
-		disk_name(sgp, 0, buf));
-	for (n = 0; n < sgp->minors - 1; n++) {
-		if (!sgp->part[n])
-			continue;
-		if (sgp->part[n]->nr_sects == 0)
-			continue;
-		seq_printf(part, "%4d  %4d %10llu %s\n",
-			sgp->major, n + 1 + sgp->first_minor,
-			(unsigned long long)sgp->part[n]->nr_sects >> 1 ,
-			disk_name(sgp, n + 1, buf));
-	}
-
-	return 0;
-}
-
-struct seq_operations partitions_op = {
-	.start =part_start,
-	.next =	part_next,
-	.stop =	part_stop,
-	.show =	show_partition
-};
-#endif
-
-
-extern int blk_dev_init(void);
-
-static struct kobject *base_probe(dev_t dev, int *part, void *data)
-{
-	if (request_module("block-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
-		/* Make old-style 2.4 aliases work */
-		request_module("block-major-%d", MAJOR(dev));
-	return NULL;
-}
-
-static int __init genhd_device_init(void)
-{
-	bdev_map = kobj_map_init(base_probe, &block_subsys_sem);
-	blk_dev_init();
-	subsystem_register(&block_subsys);
-	return 0;
-}
-
-subsys_initcall(genhd_device_init);
-
-
-
-/*
- * kobject & sysfs bindings for block devices
- */
-static ssize_t disk_attr_show(struct kobject *kobj, struct attribute *attr,
-			      char *page)
-{
-	struct gendisk *disk = to_disk(kobj);
-	struct disk_attribute *disk_attr =
-		container_of(attr,struct disk_attribute,attr);
-	ssize_t ret = -EIO;
-
-	if (disk_attr->show)
-		ret = disk_attr->show(disk,page);
-	return ret;
-}
-
-static ssize_t disk_attr_store(struct kobject * kobj, struct attribute * attr,
-			       const char *page, size_t count)
-{
-	struct gendisk *disk = to_disk(kobj);
-	struct disk_attribute *disk_attr =
-		container_of(attr,struct disk_attribute,attr);
-	ssize_t ret = 0;
-
-	if (disk_attr->store)
-		ret = disk_attr->store(disk, page, count);
-	return ret;
-}
-
-static struct sysfs_ops disk_sysfs_ops = {
-	.show	= &disk_attr_show,
-	.store	= &disk_attr_store,
-};
-
-static ssize_t disk_uevent_store(struct gendisk * disk,
-				 const char *buf, size_t count)
-{
-	kobject_hotplug(&disk->kobj, KOBJ_ADD);
-	return count;
-}
-static ssize_t disk_dev_read(struct gendisk * disk, char *page)
-{
-	dev_t base = MKDEV(disk->major, disk->first_minor); 
-	return print_dev_t(page, base);
-}
-static ssize_t disk_range_read(struct gendisk * disk, char *page)
-{
-	return sprintf(page, "%d\n", disk->minors);
-}
-static ssize_t disk_removable_read(struct gendisk * disk, char *page)
-{
-	return sprintf(page, "%d\n",
-		       (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
-
-}
-static ssize_t disk_size_read(struct gendisk * disk, char *page)
-{
-	return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk));
-}
-
-static ssize_t disk_stats_read(struct gendisk * disk, char *page)
-{
-	preempt_disable();
-	disk_round_stats(disk);
-	preempt_enable();
-	return sprintf(page,
-		"%8u %8u %8llu %8u "
-		"%8u %8u %8llu %8u "
-		"%8u %8u %8u"
-		"\n",
-		disk_stat_read(disk, ios[0]), disk_stat_read(disk, merges[0]),
-		(unsigned long long)disk_stat_read(disk, sectors[0]),
-		jiffies_to_msecs(disk_stat_read(disk, ticks[0])),
-		disk_stat_read(disk, ios[1]), disk_stat_read(disk, merges[1]),
-		(unsigned long long)disk_stat_read(disk, sectors[1]),
-		jiffies_to_msecs(disk_stat_read(disk, ticks[1])),
-		disk->in_flight,
-		jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
-		jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
-}
-static struct disk_attribute disk_attr_uevent = {
-	.attr = {.name = "uevent", .mode = S_IWUSR },
-	.store	= disk_uevent_store
-};
-static struct disk_attribute disk_attr_dev = {
-	.attr = {.name = "dev", .mode = S_IRUGO },
-	.show	= disk_dev_read
-};
-static struct disk_attribute disk_attr_range = {
-	.attr = {.name = "range", .mode = S_IRUGO },
-	.show	= disk_range_read
-};
-static struct disk_attribute disk_attr_removable = {
-	.attr = {.name = "removable", .mode = S_IRUGO },
-	.show	= disk_removable_read
-};
-static struct disk_attribute disk_attr_size = {
-	.attr = {.name = "size", .mode = S_IRUGO },
-	.show	= disk_size_read
-};
-static struct disk_attribute disk_attr_stat = {
-	.attr = {.name = "stat", .mode = S_IRUGO },
-	.show	= disk_stats_read
-};
-
-static struct attribute * default_attrs[] = {
-	&disk_attr_uevent.attr,
-	&disk_attr_dev.attr,
-	&disk_attr_range.attr,
-	&disk_attr_removable.attr,
-	&disk_attr_size.attr,
-	&disk_attr_stat.attr,
-	NULL,
-};
-
-static void disk_release(struct kobject * kobj)
-{
-	struct gendisk *disk = to_disk(kobj);
-	kfree(disk->random);
-	kfree(disk->part);
-	free_disk_stats(disk);
-	kfree(disk);
-}
-
-static struct kobj_type ktype_block = {
-	.release	= disk_release,
-	.sysfs_ops	= &disk_sysfs_ops,
-	.default_attrs	= default_attrs,
-};
-
-extern struct kobj_type ktype_part;
-
-static int block_hotplug_filter(struct kset *kset, struct kobject *kobj)
-{
-	struct kobj_type *ktype = get_ktype(kobj);
-
-	return ((ktype == &ktype_block) || (ktype == &ktype_part));
-}
-
-static int block_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
-			 int num_envp, char *buffer, int buffer_size)
-{
-	struct kobj_type *ktype = get_ktype(kobj);
-	struct device *physdev;
-	struct gendisk *disk;
-	struct hd_struct *part;
-	int length = 0;
-	int i = 0;
-
-	if (ktype == &ktype_block) {
-		disk = container_of(kobj, struct gendisk, kobj);
-		add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
-				    &length, "MINOR=%u", disk->first_minor);
-	} else if (ktype == &ktype_part) {
-		disk = container_of(kobj->parent, struct gendisk, kobj);
-		part = container_of(kobj, struct hd_struct, kobj);
-		add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
-				    &length, "MINOR=%u",
-				    disk->first_minor + part->partno);
-	} else
-		return 0;
-
-	add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size, &length,
-			    "MAJOR=%u", disk->major);
-
-	/* add physical device, backing this device  */
-	physdev = disk->driverfs_dev;
-	if (physdev) {
-		char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL);
-
-		add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
-				    &length, "PHYSDEVPATH=%s", path);
-		kfree(path);
-
-		if (physdev->bus)
-			add_hotplug_env_var(envp, num_envp, &i,
-					    buffer, buffer_size, &length,
-					    "PHYSDEVBUS=%s",
-					    physdev->bus->name);
-
-		if (physdev->driver)
-			add_hotplug_env_var(envp, num_envp, &i,
-					    buffer, buffer_size, &length,
-					    "PHYSDEVDRIVER=%s",
-					    physdev->driver->name);
-	}
-
-	/* terminate, set to next free slot, shrink available space */
-	envp[i] = NULL;
-	envp = &envp[i];
-	num_envp -= i;
-	buffer = &buffer[length];
-	buffer_size -= length;
-
-	return 0;
-}
-
-static struct kset_hotplug_ops block_hotplug_ops = {
-	.filter		= block_hotplug_filter,
-	.hotplug	= block_hotplug,
-};
-
-/* declare block_subsys. */
-static decl_subsys(block, &ktype_block, &block_hotplug_ops);
-
-
-/*
- * aggregate disk stat collector.  Uses the same stats that the sysfs
- * entries do, above, but makes them available through one seq_file.
- * Watching a few disks may be efficient through sysfs, but watching
- * all of them will be more efficient through this interface.
- *
- * The output looks suspiciously like /proc/partitions with a bunch of
- * extra fields.
- */
-
-/* iterator */
-static void *diskstats_start(struct seq_file *part, loff_t *pos)
-{
-	loff_t k = *pos;
-	struct list_head *p;
-
-	down(&block_subsys_sem);
-	list_for_each(p, &block_subsys.kset.list)
-		if (!k--)
-			return list_entry(p, struct gendisk, kobj.entry);
-	return NULL;
-}
-
-static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
-{
-	struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
-	++*pos;
-	return p==&block_subsys.kset.list ? NULL :
-		list_entry(p, struct gendisk, kobj.entry);
-}
-
-static void diskstats_stop(struct seq_file *part, void *v)
-{
-	up(&block_subsys_sem);
-}
-
-static int diskstats_show(struct seq_file *s, void *v)
-{
-	struct gendisk *gp = v;
-	char buf[BDEVNAME_SIZE];
-	int n = 0;
-
-	/*
-	if (&sgp->kobj.entry == block_subsys.kset.list.next)
-		seq_puts(s,	"major minor name"
-				"     rio rmerge rsect ruse wio wmerge "
-				"wsect wuse running use aveq"
-				"\n\n");
-	*/
- 
-	preempt_disable();
-	disk_round_stats(gp);
-	preempt_enable();
-	seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
-		gp->major, n + gp->first_minor, disk_name(gp, n, buf),
-		disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
-		(unsigned long long)disk_stat_read(gp, sectors[0]),
-		jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
-		disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
-		(unsigned long long)disk_stat_read(gp, sectors[1]),
-		jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
-		gp->in_flight,
-		jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
-		jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
-
-	/* now show all non-0 size partitions of it */
-	for (n = 0; n < gp->minors - 1; n++) {
-		struct hd_struct *hd = gp->part[n];
-
-		if (hd && hd->nr_sects)
-			seq_printf(s, "%4d %4d %s %u %u %u %u\n",
-				gp->major, n + gp->first_minor + 1,
-				disk_name(gp, n + 1, buf),
-				hd->ios[0], hd->sectors[0],
-				hd->ios[1], hd->sectors[1]);
-	}
- 
-	return 0;
-}
-
-struct seq_operations diskstats_op = {
-	.start	= diskstats_start,
-	.next	= diskstats_next,
-	.stop	= diskstats_stop,
-	.show	= diskstats_show
-};
-
-struct gendisk *alloc_disk(int minors)
-{
-	return alloc_disk_node(minors, -1);
-}
-
-struct gendisk *alloc_disk_node(int minors, int node_id)
-{
-	struct gendisk *disk;
-
-	disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
-	if (disk) {
-		memset(disk, 0, sizeof(struct gendisk));
-		if (!init_disk_stats(disk)) {
-			kfree(disk);
-			return NULL;
-		}
-		if (minors > 1) {
-			int size = (minors - 1) * sizeof(struct hd_struct *);
-			disk->part = kmalloc_node(size, GFP_KERNEL, node_id);
-			if (!disk->part) {
-				kfree(disk);
-				return NULL;
-			}
-			memset(disk->part, 0, size);
-		}
-		disk->minors = minors;
-		kobj_set_kset_s(disk,block_subsys);
-		kobject_init(&disk->kobj);
-		rand_initialize_disk(disk);
-	}
-	return disk;
-}
-
-EXPORT_SYMBOL(alloc_disk);
-EXPORT_SYMBOL(alloc_disk_node);
-
-struct kobject *get_disk(struct gendisk *disk)
-{
-	struct module *owner;
-	struct kobject *kobj;
-
-	if (!disk->fops)
-		return NULL;
-	owner = disk->fops->owner;
-	if (owner && !try_module_get(owner))
-		return NULL;
-	kobj = kobject_get(&disk->kobj);
-	if (kobj == NULL) {
-		module_put(owner);
-		return NULL;
-	}
-	return kobj;
-
-}
-
-EXPORT_SYMBOL(get_disk);
-
-void put_disk(struct gendisk *disk)
-{
-	if (disk)
-		kobject_put(&disk->kobj);
-}
-
-EXPORT_SYMBOL(put_disk);
-
-void set_device_ro(struct block_device *bdev, int flag)
-{
-	if (bdev->bd_contains != bdev)
-		bdev->bd_part->policy = flag;
-	else
-		bdev->bd_disk->policy = flag;
-}
-
-EXPORT_SYMBOL(set_device_ro);
-
-void set_disk_ro(struct gendisk *disk, int flag)
-{
-	int i;
-	disk->policy = flag;
-	for (i = 0; i < disk->minors - 1; i++)
-		if (disk->part[i]) disk->part[i]->policy = flag;
-}
-
-EXPORT_SYMBOL(set_disk_ro);
-
-int bdev_read_only(struct block_device *bdev)
-{
-	if (!bdev)
-		return 0;
-	else if (bdev->bd_contains != bdev)
-		return bdev->bd_part->policy;
-	else
-		return bdev->bd_disk->policy;
-}
-
-EXPORT_SYMBOL(bdev_read_only);
-
-int invalidate_partition(struct gendisk *disk, int index)
-{
-	int res = 0;
-	struct block_device *bdev = bdget_disk(disk, index);
-	if (bdev) {
-		fsync_bdev(bdev);
-		res = __invalidate_device(bdev);
-		bdput(bdev);
-	}
-	return res;
-}
-
-EXPORT_SYMBOL(invalidate_partition);
diff --git a/drivers/block/ioctl.c b/drivers/block/ioctl.c
deleted file mode 100644
index 6e278474f9a8..000000000000
--- a/drivers/block/ioctl.c
+++ /dev/null
@@ -1,275 +0,0 @@
-#include <linux/sched.h>		/* for capable() */
-#include <linux/blkdev.h>
-#include <linux/blkpg.h>
-#include <linux/backing-dev.h>
-#include <linux/buffer_head.h>
-#include <linux/smp_lock.h>
-#include <asm/uaccess.h>
-
-static int blkpg_ioctl(struct block_device *bdev, struct blkpg_ioctl_arg __user *arg)
-{
-	struct block_device *bdevp;
-	struct gendisk *disk;
-	struct blkpg_ioctl_arg a;
-	struct blkpg_partition p;
-	long long start, length;
-	int part;
-	int i;
-
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
-	if (copy_from_user(&a, arg, sizeof(struct blkpg_ioctl_arg)))
-		return -EFAULT;
-	if (copy_from_user(&p, a.data, sizeof(struct blkpg_partition)))
-		return -EFAULT;
-	disk = bdev->bd_disk;
-	if (bdev != bdev->bd_contains)
-		return -EINVAL;
-	part = p.pno;
-	if (part <= 0 || part >= disk->minors)
-		return -EINVAL;
-	switch (a.op) {
-		case BLKPG_ADD_PARTITION:
-			start = p.start >> 9;
-			length = p.length >> 9;
-			/* check for fit in a hd_struct */ 
-			if (sizeof(sector_t) == sizeof(long) && 
-			    sizeof(long long) > sizeof(long)) {
-				long pstart = start, plength = length;
-				if (pstart != start || plength != length
-				    || pstart < 0 || plength < 0)
-					return -EINVAL;
-			}
-			/* partition number in use? */
-			down(&bdev->bd_sem);
-			if (disk->part[part - 1]) {
-				up(&bdev->bd_sem);
-				return -EBUSY;
-			}
-			/* overlap? */
-			for (i = 0; i < disk->minors - 1; i++) {
-				struct hd_struct *s = disk->part[i];
-
-				if (!s)
-					continue;
-				if (!(start+length <= s->start_sect ||
-				      start >= s->start_sect + s->nr_sects)) {
-					up(&bdev->bd_sem);
-					return -EBUSY;
-				}
-			}
-			/* all seems OK */
-			add_partition(disk, part, start, length);
-			up(&bdev->bd_sem);
-			return 0;
-		case BLKPG_DEL_PARTITION:
-			if (!disk->part[part-1])
-				return -ENXIO;
-			if (disk->part[part - 1]->nr_sects == 0)
-				return -ENXIO;
-			bdevp = bdget_disk(disk, part);
-			if (!bdevp)
-				return -ENOMEM;
-			down(&bdevp->bd_sem);
-			if (bdevp->bd_openers) {
-				up(&bdevp->bd_sem);
-				bdput(bdevp);
-				return -EBUSY;
-			}
-			/* all seems OK */
-			fsync_bdev(bdevp);
-			invalidate_bdev(bdevp, 0);
-
-			down(&bdev->bd_sem);
-			delete_partition(disk, part);
-			up(&bdev->bd_sem);
-			up(&bdevp->bd_sem);
-			bdput(bdevp);
-
-			return 0;
-		default:
-			return -EINVAL;
-	}
-}
-
-static int blkdev_reread_part(struct block_device *bdev)
-{
-	struct gendisk *disk = bdev->bd_disk;
-	int res;
-
-	if (disk->minors == 1 || bdev != bdev->bd_contains)
-		return -EINVAL;
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
-	if (down_trylock(&bdev->bd_sem))
-		return -EBUSY;
-	res = rescan_partitions(disk, bdev);
-	up(&bdev->bd_sem);
-	return res;
-}
-
-static int put_ushort(unsigned long arg, unsigned short val)
-{
-	return put_user(val, (unsigned short __user *)arg);
-}
-
-static int put_int(unsigned long arg, int val)
-{
-	return put_user(val, (int __user *)arg);
-}
-
-static int put_long(unsigned long arg, long val)
-{
-	return put_user(val, (long __user *)arg);
-}
-
-static int put_ulong(unsigned long arg, unsigned long val)
-{
-	return put_user(val, (unsigned long __user *)arg);
-}
-
-static int put_u64(unsigned long arg, u64 val)
-{
-	return put_user(val, (u64 __user *)arg);
-}
-
-static int blkdev_locked_ioctl(struct file *file, struct block_device *bdev,
-				unsigned cmd, unsigned long arg)
-{
-	struct backing_dev_info *bdi;
-	int ret, n;
-
-	switch (cmd) {
-	case BLKRAGET:
-	case BLKFRAGET:
-		if (!arg)
-			return -EINVAL;
-		bdi = blk_get_backing_dev_info(bdev);
-		if (bdi == NULL)
-			return -ENOTTY;
-		return put_long(arg, (bdi->ra_pages * PAGE_CACHE_SIZE) / 512);
-	case BLKROGET:
-		return put_int(arg, bdev_read_only(bdev) != 0);
-	case BLKBSZGET: /* get the logical block size (cf. BLKSSZGET) */
-		return put_int(arg, block_size(bdev));
-	case BLKSSZGET: /* get block device hardware sector size */
-		return put_int(arg, bdev_hardsect_size(bdev));
-	case BLKSECTGET:
-		return put_ushort(arg, bdev_get_queue(bdev)->max_sectors);
-	case BLKRASET:
-	case BLKFRASET:
-		if(!capable(CAP_SYS_ADMIN))
-			return -EACCES;
-		bdi = blk_get_backing_dev_info(bdev);
-		if (bdi == NULL)
-			return -ENOTTY;
-		bdi->ra_pages = (arg * 512) / PAGE_CACHE_SIZE;
-		return 0;
-	case BLKBSZSET:
-		/* set the logical block size */
-		if (!capable(CAP_SYS_ADMIN))
-			return -EACCES;
-		if (!arg)
-			return -EINVAL;
-		if (get_user(n, (int __user *) arg))
-			return -EFAULT;
-		if (bd_claim(bdev, file) < 0)
-			return -EBUSY;
-		ret = set_blocksize(bdev, n);
-		bd_release(bdev);
-		return ret;
-	case BLKPG:
-		return blkpg_ioctl(bdev, (struct blkpg_ioctl_arg __user *) arg);
-	case BLKRRPART:
-		return blkdev_reread_part(bdev);
-	case BLKGETSIZE:
-		if ((bdev->bd_inode->i_size >> 9) > ~0UL)
-			return -EFBIG;
-		return put_ulong(arg, bdev->bd_inode->i_size >> 9);
-	case BLKGETSIZE64:
-		return put_u64(arg, bdev->bd_inode->i_size);
-	}
-	return -ENOIOCTLCMD;
-}
-
-static int blkdev_driver_ioctl(struct inode *inode, struct file *file,
-		struct gendisk *disk, unsigned cmd, unsigned long arg)
-{
-	int ret;
-	if (disk->fops->unlocked_ioctl)
-		return disk->fops->unlocked_ioctl(file, cmd, arg);
-
-	if (disk->fops->ioctl) {
-		lock_kernel();
-		ret = disk->fops->ioctl(inode, file, cmd, arg);
-		unlock_kernel();
-		return ret;
-	}
-
-	return -ENOTTY;
-}
-
-int blkdev_ioctl(struct inode *inode, struct file *file, unsigned cmd,
-			unsigned long arg)
-{
-	struct block_device *bdev = inode->i_bdev;
-	struct gendisk *disk = bdev->bd_disk;
-	int ret, n;
-
-	switch(cmd) {
-	case BLKFLSBUF:
-		if (!capable(CAP_SYS_ADMIN))
-			return -EACCES;
-
-		ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
-		/* -EINVAL to handle old uncorrected drivers */
-		if (ret != -EINVAL && ret != -ENOTTY)
-			return ret;
-
-		lock_kernel();
-		fsync_bdev(bdev);
-		invalidate_bdev(bdev, 0);
-		unlock_kernel();
-		return 0;
-
-	case BLKROSET:
-		ret = blkdev_driver_ioctl(inode, file, disk, cmd, arg);
-		/* -EINVAL to handle old uncorrected drivers */
-		if (ret != -EINVAL && ret != -ENOTTY)
-			return ret;
-		if (!capable(CAP_SYS_ADMIN))
-			return -EACCES;
-		if (get_user(n, (int __user *)(arg)))
-			return -EFAULT;
-		lock_kernel();
-		set_device_ro(bdev, n);
-		unlock_kernel();
-		return 0;
-	}
-
-	lock_kernel();
-	ret = blkdev_locked_ioctl(file, bdev, cmd, arg);
-	unlock_kernel();
-	if (ret != -ENOIOCTLCMD)
-		return ret;
-
-	return blkdev_driver_ioctl(inode, file, disk, cmd, arg);
-}
-
-/* Most of the generic ioctls are handled in the normal fallback path.
-   This assumes the blkdev's low level compat_ioctl always returns
-   ENOIOCTLCMD for unknown ioctls. */
-long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
-{
-	struct block_device *bdev = file->f_dentry->d_inode->i_bdev;
-	struct gendisk *disk = bdev->bd_disk;
-	int ret = -ENOIOCTLCMD;
-	if (disk->fops->compat_ioctl) {
-		lock_kernel();
-		ret = disk->fops->compat_ioctl(file, cmd, arg);
-		unlock_kernel();
-	}
-	return ret;
-}
-
-EXPORT_SYMBOL_GPL(blkdev_ioctl);
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
deleted file mode 100644
index 2747741677fb..000000000000
--- a/drivers/block/ll_rw_blk.c
+++ /dev/null
@@ -1,3613 +0,0 @@
-/*
- *  linux/drivers/block/ll_rw_blk.c
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- * Copyright (C) 1994,      Karl Keyte: Added support for disk statistics
- * Elevator latency, (C) 2000  Andrea Arcangeli <andrea@suse.de> SuSE
- * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
- * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> -  July2000
- * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
- */
-
-/*
- * This handles all read/write requests to block devices
- */
-#include <linux/config.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/backing-dev.h>
-#include <linux/bio.h>
-#include <linux/blkdev.h>
-#include <linux/highmem.h>
-#include <linux/mm.h>
-#include <linux/kernel_stat.h>
-#include <linux/string.h>
-#include <linux/init.h>
-#include <linux/bootmem.h>	/* for max_pfn/max_low_pfn */
-#include <linux/completion.h>
-#include <linux/slab.h>
-#include <linux/swap.h>
-#include <linux/writeback.h>
-#include <linux/blkdev.h>
-
-/*
- * for max sense size
- */
-#include <scsi/scsi_cmnd.h>
-
-static void blk_unplug_work(void *data);
-static void blk_unplug_timeout(unsigned long data);
-static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io);
-
-/*
- * For the allocated request tables
- */
-static kmem_cache_t *request_cachep;
-
-/*
- * For queue allocation
- */
-static kmem_cache_t *requestq_cachep;
-
-/*
- * For io context allocations
- */
-static kmem_cache_t *iocontext_cachep;
-
-static wait_queue_head_t congestion_wqh[2] = {
-		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
-		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])
-	};
-
-/*
- * Controlling structure to kblockd
- */
-static struct workqueue_struct *kblockd_workqueue; 
-
-unsigned long blk_max_low_pfn, blk_max_pfn;
-
-EXPORT_SYMBOL(blk_max_low_pfn);
-EXPORT_SYMBOL(blk_max_pfn);
-
-/* Amount of time in which a process may batch requests */
-#define BLK_BATCH_TIME	(HZ/50UL)
-
-/* Number of requests a "batching" process may submit */
-#define BLK_BATCH_REQ	32
-
-/*
- * Return the threshold (number of used requests) at which the queue is
- * considered to be congested.  It include a little hysteresis to keep the
- * context switch rate down.
- */
-static inline int queue_congestion_on_threshold(struct request_queue *q)
-{
-	return q->nr_congestion_on;
-}
-
-/*
- * The threshold at which a queue is considered to be uncongested
- */
-static inline int queue_congestion_off_threshold(struct request_queue *q)
-{
-	return q->nr_congestion_off;
-}
-
-static void blk_queue_congestion_threshold(struct request_queue *q)
-{
-	int nr;
-
-	nr = q->nr_requests - (q->nr_requests / 8) + 1;
-	if (nr > q->nr_requests)
-		nr = q->nr_requests;
-	q->nr_congestion_on = nr;
-
-	nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1;
-	if (nr < 1)
-		nr = 1;
-	q->nr_congestion_off = nr;
-}
-
-/*
- * A queue has just exitted congestion.  Note this in the global counter of
- * congested queues, and wake up anyone who was waiting for requests to be
- * put back.
- */
-static void clear_queue_congested(request_queue_t *q, int rw)
-{
-	enum bdi_state bit;
-	wait_queue_head_t *wqh = &congestion_wqh[rw];
-
-	bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
-	clear_bit(bit, &q->backing_dev_info.state);
-	smp_mb__after_clear_bit();
-	if (waitqueue_active(wqh))
-		wake_up(wqh);
-}
-
-/*
- * A queue has just entered congestion.  Flag that in the queue's VM-visible
- * state flags and increment the global gounter of congested queues.
- */
-static void set_queue_congested(request_queue_t *q, int rw)
-{
-	enum bdi_state bit;
-
-	bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested;
-	set_bit(bit, &q->backing_dev_info.state);
-}
-
-/**
- * blk_get_backing_dev_info - get the address of a queue's backing_dev_info
- * @bdev:	device
- *
- * Locates the passed device's request queue and returns the address of its
- * backing_dev_info
- *
- * Will return NULL if the request queue cannot be located.
- */
-struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
-{
-	struct backing_dev_info *ret = NULL;
-	request_queue_t *q = bdev_get_queue(bdev);
-
-	if (q)
-		ret = &q->backing_dev_info;
-	return ret;
-}
-
-EXPORT_SYMBOL(blk_get_backing_dev_info);
-
-void blk_queue_activity_fn(request_queue_t *q, activity_fn *fn, void *data)
-{
-	q->activity_fn = fn;
-	q->activity_data = data;
-}
-
-EXPORT_SYMBOL(blk_queue_activity_fn);
-
-/**
- * blk_queue_prep_rq - set a prepare_request function for queue
- * @q:		queue
- * @pfn:	prepare_request function
- *
- * It's possible for a queue to register a prepare_request callback which
- * is invoked before the request is handed to the request_fn. The goal of
- * the function is to prepare a request for I/O, it can be used to build a
- * cdb from the request data for instance.
- *
- */
-void blk_queue_prep_rq(request_queue_t *q, prep_rq_fn *pfn)
-{
-	q->prep_rq_fn = pfn;
-}
-
-EXPORT_SYMBOL(blk_queue_prep_rq);
-
-/**
- * blk_queue_merge_bvec - set a merge_bvec function for queue
- * @q:		queue
- * @mbfn:	merge_bvec_fn
- *
- * Usually queues have static limitations on the max sectors or segments that
- * we can put in a request. Stacking drivers may have some settings that
- * are dynamic, and thus we have to query the queue whether it is ok to
- * add a new bio_vec to a bio at a given offset or not. If the block device
- * has such limitations, it needs to register a merge_bvec_fn to control
- * the size of bio's sent to it. Note that a block device *must* allow a
- * single page to be added to an empty bio. The block device driver may want
- * to use the bio_split() function to deal with these bio's. By default
- * no merge_bvec_fn is defined for a queue, and only the fixed limits are
- * honored.
- */
-void blk_queue_merge_bvec(request_queue_t *q, merge_bvec_fn *mbfn)
-{
-	q->merge_bvec_fn = mbfn;
-}
-
-EXPORT_SYMBOL(blk_queue_merge_bvec);
-
-/**
- * blk_queue_make_request - define an alternate make_request function for a device
- * @q:  the request queue for the device to be affected
- * @mfn: the alternate make_request function
- *
- * Description:
- *    The normal way for &struct bios to be passed to a device
- *    driver is for them to be collected into requests on a request
- *    queue, and then to allow the device driver to select requests
- *    off that queue when it is ready.  This works well for many block
- *    devices. However some block devices (typically virtual devices
- *    such as md or lvm) do not benefit from the processing on the
- *    request queue, and are served best by having the requests passed
- *    directly to them.  This can be achieved by providing a function
- *    to blk_queue_make_request().
- *
- * Caveat:
- *    The driver that does this *must* be able to deal appropriately
- *    with buffers in "highmemory". This can be accomplished by either calling
- *    __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
- *    blk_queue_bounce() to create a buffer in normal memory.
- **/
-void blk_queue_make_request(request_queue_t * q, make_request_fn * mfn)
-{
-	/*
-	 * set defaults
-	 */
-	q->nr_requests = BLKDEV_MAX_RQ;
-	blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
-	blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
-	q->make_request_fn = mfn;
-	q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
-	q->backing_dev_info.state = 0;
-	q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
-	blk_queue_max_sectors(q, MAX_SECTORS);
-	blk_queue_hardsect_size(q, 512);
-	blk_queue_dma_alignment(q, 511);
-	blk_queue_congestion_threshold(q);
-	q->nr_batching = BLK_BATCH_REQ;
-
-	q->unplug_thresh = 4;		/* hmm */
-	q->unplug_delay = (3 * HZ) / 1000;	/* 3 milliseconds */
-	if (q->unplug_delay == 0)
-		q->unplug_delay = 1;
-
-	INIT_WORK(&q->unplug_work, blk_unplug_work, q);
-
-	q->unplug_timer.function = blk_unplug_timeout;
-	q->unplug_timer.data = (unsigned long)q;
-
-	/*
-	 * by default assume old behaviour and bounce for any highmem page
-	 */
-	blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
-
-	blk_queue_activity_fn(q, NULL, NULL);
-}
-
-EXPORT_SYMBOL(blk_queue_make_request);
-
-static inline void rq_init(request_queue_t *q, struct request *rq)
-{
-	INIT_LIST_HEAD(&rq->queuelist);
-
-	rq->errors = 0;
-	rq->rq_status = RQ_ACTIVE;
-	rq->bio = rq->biotail = NULL;
-	rq->ioprio = 0;
-	rq->buffer = NULL;
-	rq->ref_count = 1;
-	rq->q = q;
-	rq->waiting = NULL;
-	rq->special = NULL;
-	rq->data_len = 0;
-	rq->data = NULL;
-	rq->nr_phys_segments = 0;
-	rq->sense = NULL;
-	rq->end_io = NULL;
-	rq->end_io_data = NULL;
-}
-
-/**
- * blk_queue_ordered - does this queue support ordered writes
- * @q:     the request queue
- * @flag:  see below
- *
- * Description:
- *   For journalled file systems, doing ordered writes on a commit
- *   block instead of explicitly doing wait_on_buffer (which is bad
- *   for performance) can be a big win. Block drivers supporting this
- *   feature should call this function and indicate so.
- *
- **/
-void blk_queue_ordered(request_queue_t *q, int flag)
-{
-	switch (flag) {
-		case QUEUE_ORDERED_NONE:
-			if (q->flush_rq)
-				kmem_cache_free(request_cachep, q->flush_rq);
-			q->flush_rq = NULL;
-			q->ordered = flag;
-			break;
-		case QUEUE_ORDERED_TAG:
-			q->ordered = flag;
-			break;
-		case QUEUE_ORDERED_FLUSH:
-			q->ordered = flag;
-			if (!q->flush_rq)
-				q->flush_rq = kmem_cache_alloc(request_cachep,
-								GFP_KERNEL);
-			break;
-		default:
-			printk("blk_queue_ordered: bad value %d\n", flag);
-			break;
-	}
-}
-
-EXPORT_SYMBOL(blk_queue_ordered);
-
-/**
- * blk_queue_issue_flush_fn - set function for issuing a flush
- * @q:     the request queue
- * @iff:   the function to be called issuing the flush
- *
- * Description:
- *   If a driver supports issuing a flush command, the support is notified
- *   to the block layer by defining it through this call.
- *
- **/
-void blk_queue_issue_flush_fn(request_queue_t *q, issue_flush_fn *iff)
-{
-	q->issue_flush_fn = iff;
-}
-
-EXPORT_SYMBOL(blk_queue_issue_flush_fn);
-
-/*
- * Cache flushing for ordered writes handling
- */
-static void blk_pre_flush_end_io(struct request *flush_rq)
-{
-	struct request *rq = flush_rq->end_io_data;
-	request_queue_t *q = rq->q;
-
-	elv_completed_request(q, flush_rq);
-
-	rq->flags |= REQ_BAR_PREFLUSH;
-
-	if (!flush_rq->errors)
-		elv_requeue_request(q, rq);
-	else {
-		q->end_flush_fn(q, flush_rq);
-		clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
-		q->request_fn(q);
-	}
-}
-
-static void blk_post_flush_end_io(struct request *flush_rq)
-{
-	struct request *rq = flush_rq->end_io_data;
-	request_queue_t *q = rq->q;
-
-	elv_completed_request(q, flush_rq);
-
-	rq->flags |= REQ_BAR_POSTFLUSH;
-
-	q->end_flush_fn(q, flush_rq);
-	clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
-	q->request_fn(q);
-}
-
-struct request *blk_start_pre_flush(request_queue_t *q, struct request *rq)
-{
-	struct request *flush_rq = q->flush_rq;
-
-	BUG_ON(!blk_barrier_rq(rq));
-
-	if (test_and_set_bit(QUEUE_FLAG_FLUSH, &q->queue_flags))
-		return NULL;
-
-	rq_init(q, flush_rq);
-	flush_rq->elevator_private = NULL;
-	flush_rq->flags = REQ_BAR_FLUSH;
-	flush_rq->rq_disk = rq->rq_disk;
-	flush_rq->rl = NULL;
-
-	/*
-	 * prepare_flush returns 0 if no flush is needed, just mark both
-	 * pre and post flush as done in that case
-	 */
-	if (!q->prepare_flush_fn(q, flush_rq)) {
-		rq->flags |= REQ_BAR_PREFLUSH | REQ_BAR_POSTFLUSH;
-		clear_bit(QUEUE_FLAG_FLUSH, &q->queue_flags);
-		return rq;
-	}
-
-	/*
-	 * some drivers dequeue requests right away, some only after io
-	 * completion. make sure the request is dequeued.
-	 */
-	if (!list_empty(&rq->queuelist))
-		blkdev_dequeue_request(rq);
-
-	flush_rq->end_io_data = rq;
-	flush_rq->end_io = blk_pre_flush_end_io;
-
-	__elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0);
-	return flush_rq;
-}
-
-static void blk_start_post_flush(request_queue_t *q, struct request *rq)
-{
-	struct request *flush_rq = q->flush_rq;
-
-	BUG_ON(!blk_barrier_rq(rq));
-
-	rq_init(q, flush_rq);
-	flush_rq->elevator_private = NULL;
-	flush_rq->flags = REQ_BAR_FLUSH;
-	flush_rq->rq_disk = rq->rq_disk;
-	flush_rq->rl = NULL;
-
-	if (q->prepare_flush_fn(q, flush_rq)) {
-		flush_rq->end_io_data = rq;
-		flush_rq->end_io = blk_post_flush_end_io;
-
-		__elv_add_request(q, flush_rq, ELEVATOR_INSERT_FRONT, 0);
-		q->request_fn(q);
-	}
-}
-
-static inline int blk_check_end_barrier(request_queue_t *q, struct request *rq,
-					int sectors)
-{
-	if (sectors > rq->nr_sectors)
-		sectors = rq->nr_sectors;
-
-	rq->nr_sectors -= sectors;
-	return rq->nr_sectors;
-}
-
-static int __blk_complete_barrier_rq(request_queue_t *q, struct request *rq,
-				     int sectors, int queue_locked)
-{
-	if (q->ordered != QUEUE_ORDERED_FLUSH)
-		return 0;
-	if (!blk_fs_request(rq) || !blk_barrier_rq(rq))
-		return 0;
-	if (blk_barrier_postflush(rq))
-		return 0;
-
-	if (!blk_check_end_barrier(q, rq, sectors)) {
-		unsigned long flags = 0;
-
-		if (!queue_locked)
-			spin_lock_irqsave(q->queue_lock, flags);
-
-		blk_start_post_flush(q, rq);
-
-		if (!queue_locked)
-			spin_unlock_irqrestore(q->queue_lock, flags);
-	}
-
-	return 1;
-}
-
-/**
- * blk_complete_barrier_rq - complete possible barrier request
- * @q:  the request queue for the device
- * @rq:  the request
- * @sectors:  number of sectors to complete
- *
- * Description:
- *   Used in driver end_io handling to determine whether to postpone
- *   completion of a barrier request until a post flush has been done. This
- *   is the unlocked variant, used if the caller doesn't already hold the
- *   queue lock.
- **/
-int blk_complete_barrier_rq(request_queue_t *q, struct request *rq, int sectors)
-{
-	return __blk_complete_barrier_rq(q, rq, sectors, 0);
-}
-EXPORT_SYMBOL(blk_complete_barrier_rq);
-
-/**
- * blk_complete_barrier_rq_locked - complete possible barrier request
- * @q:  the request queue for the device
- * @rq:  the request
- * @sectors:  number of sectors to complete
- *
- * Description:
- *   See blk_complete_barrier_rq(). This variant must be used if the caller
- *   holds the queue lock.
- **/
-int blk_complete_barrier_rq_locked(request_queue_t *q, struct request *rq,
-				   int sectors)
-{
-	return __blk_complete_barrier_rq(q, rq, sectors, 1);
-}
-EXPORT_SYMBOL(blk_complete_barrier_rq_locked);
-
-/**
- * blk_queue_bounce_limit - set bounce buffer limit for queue
- * @q:  the request queue for the device
- * @dma_addr:   bus address limit
- *
- * Description:
- *    Different hardware can have different requirements as to what pages
- *    it can do I/O directly to. A low level driver can call
- *    blk_queue_bounce_limit to have lower memory pages allocated as bounce
- *    buffers for doing I/O to pages residing above @page. By default
- *    the block layer sets this to the highest numbered "low" memory page.
- **/
-void blk_queue_bounce_limit(request_queue_t *q, u64 dma_addr)
-{
-	unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT;
-
-	/*
-	 * set appropriate bounce gfp mask -- unfortunately we don't have a
-	 * full 4GB zone, so we have to resort to low memory for any bounces.
-	 * ISA has its own < 16MB zone.
-	 */
-	if (bounce_pfn < blk_max_low_pfn) {
-		BUG_ON(dma_addr < BLK_BOUNCE_ISA);
-		init_emergency_isa_pool();
-		q->bounce_gfp = GFP_NOIO | GFP_DMA;
-	} else
-		q->bounce_gfp = GFP_NOIO;
-
-	q->bounce_pfn = bounce_pfn;
-}
-
-EXPORT_SYMBOL(blk_queue_bounce_limit);
-
-/**
- * blk_queue_max_sectors - set max sectors for a request for this queue
- * @q:  the request queue for the device
- * @max_sectors:  max sectors in the usual 512b unit
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the size of
- *    received requests.
- **/
-void blk_queue_max_sectors(request_queue_t *q, unsigned short max_sectors)
-{
-	if ((max_sectors << 9) < PAGE_CACHE_SIZE) {
-		max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
-		printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
-	}
-
-	q->max_sectors = q->max_hw_sectors = max_sectors;
-}
-
-EXPORT_SYMBOL(blk_queue_max_sectors);
-
-/**
- * blk_queue_max_phys_segments - set max phys segments for a request for this queue
- * @q:  the request queue for the device
- * @max_segments:  max number of segments
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the number of
- *    physical data segments in a request.  This would be the largest sized
- *    scatter list the driver could handle.
- **/
-void blk_queue_max_phys_segments(request_queue_t *q, unsigned short max_segments)
-{
-	if (!max_segments) {
-		max_segments = 1;
-		printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
-	}
-
-	q->max_phys_segments = max_segments;
-}
-
-EXPORT_SYMBOL(blk_queue_max_phys_segments);
-
-/**
- * blk_queue_max_hw_segments - set max hw segments for a request for this queue
- * @q:  the request queue for the device
- * @max_segments:  max number of segments
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the number of
- *    hw data segments in a request.  This would be the largest number of
- *    address/length pairs the host adapter can actually give as once
- *    to the device.
- **/
-void blk_queue_max_hw_segments(request_queue_t *q, unsigned short max_segments)
-{
-	if (!max_segments) {
-		max_segments = 1;
-		printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
-	}
-
-	q->max_hw_segments = max_segments;
-}
-
-EXPORT_SYMBOL(blk_queue_max_hw_segments);
-
-/**
- * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
- * @q:  the request queue for the device
- * @max_size:  max size of segment in bytes
- *
- * Description:
- *    Enables a low level driver to set an upper limit on the size of a
- *    coalesced segment
- **/
-void blk_queue_max_segment_size(request_queue_t *q, unsigned int max_size)
-{
-	if (max_size < PAGE_CACHE_SIZE) {
-		max_size = PAGE_CACHE_SIZE;
-		printk("%s: set to minimum %d\n", __FUNCTION__, max_size);
-	}
-
-	q->max_segment_size = max_size;
-}
-
-EXPORT_SYMBOL(blk_queue_max_segment_size);
-
-/**
- * blk_queue_hardsect_size - set hardware sector size for the queue
- * @q:  the request queue for the device
- * @size:  the hardware sector size, in bytes
- *
- * Description:
- *   This should typically be set to the lowest possible sector size
- *   that the hardware can operate on (possible without reverting to
- *   even internal read-modify-write operations). Usually the default
- *   of 512 covers most hardware.
- **/
-void blk_queue_hardsect_size(request_queue_t *q, unsigned short size)
-{
-	q->hardsect_size = size;
-}
-
-EXPORT_SYMBOL(blk_queue_hardsect_size);
-
-/*
- * Returns the minimum that is _not_ zero, unless both are zero.
- */
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
-
-/**
- * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
- * @t:	the stacking driver (top)
- * @b:  the underlying device (bottom)
- **/
-void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b)
-{
-	/* zero is "infinity" */
-	t->max_sectors = t->max_hw_sectors =
-		min_not_zero(t->max_sectors,b->max_sectors);
-
-	t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
-	t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
-	t->max_segment_size = min(t->max_segment_size,b->max_segment_size);
-	t->hardsect_size = max(t->hardsect_size,b->hardsect_size);
-}
-
-EXPORT_SYMBOL(blk_queue_stack_limits);
-
-/**
- * blk_queue_segment_boundary - set boundary rules for segment merging
- * @q:  the request queue for the device
- * @mask:  the memory boundary mask
- **/
-void blk_queue_segment_boundary(request_queue_t *q, unsigned long mask)
-{
-	if (mask < PAGE_CACHE_SIZE - 1) {
-		mask = PAGE_CACHE_SIZE - 1;
-		printk("%s: set to minimum %lx\n", __FUNCTION__, mask);
-	}
-
-	q->seg_boundary_mask = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_segment_boundary);
-
-/**
- * blk_queue_dma_alignment - set dma length and memory alignment
- * @q:     the request queue for the device
- * @mask:  alignment mask
- *
- * description:
- *    set required memory and length aligment for direct dma transactions.
- *    this is used when buiding direct io requests for the queue.
- *
- **/
-void blk_queue_dma_alignment(request_queue_t *q, int mask)
-{
-	q->dma_alignment = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_dma_alignment);
-
-/**
- * blk_queue_find_tag - find a request by its tag and queue
- *
- * @q:	 The request queue for the device
- * @tag: The tag of the request
- *
- * Notes:
- *    Should be used when a device returns a tag and you want to match
- *    it with a request.
- *
- *    no locks need be held.
- **/
-struct request *blk_queue_find_tag(request_queue_t *q, int tag)
-{
-	struct blk_queue_tag *bqt = q->queue_tags;
-
-	if (unlikely(bqt == NULL || tag >= bqt->real_max_depth))
-		return NULL;
-
-	return bqt->tag_index[tag];
-}
-
-EXPORT_SYMBOL(blk_queue_find_tag);
-
-/**
- * __blk_queue_free_tags - release tag maintenance info
- * @q:  the request queue for the device
- *
- *  Notes:
- *    blk_cleanup_queue() will take care of calling this function, if tagging
- *    has been used. So there's no need to call this directly.
- **/
-static void __blk_queue_free_tags(request_queue_t *q)
-{
-	struct blk_queue_tag *bqt = q->queue_tags;
-
-	if (!bqt)
-		return;
-
-	if (atomic_dec_and_test(&bqt->refcnt)) {
-		BUG_ON(bqt->busy);
-		BUG_ON(!list_empty(&bqt->busy_list));
-
-		kfree(bqt->tag_index);
-		bqt->tag_index = NULL;
-
-		kfree(bqt->tag_map);
-		bqt->tag_map = NULL;
-
-		kfree(bqt);
-	}
-
-	q->queue_tags = NULL;
-	q->queue_flags &= ~(1 << QUEUE_FLAG_QUEUED);
-}
-
-/**
- * blk_queue_free_tags - release tag maintenance info
- * @q:  the request queue for the device
- *
- *  Notes:
- *	This is used to disabled tagged queuing to a device, yet leave
- *	queue in function.
- **/
-void blk_queue_free_tags(request_queue_t *q)
-{
-	clear_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
-}
-
-EXPORT_SYMBOL(blk_queue_free_tags);
-
-static int
-init_tag_map(request_queue_t *q, struct blk_queue_tag *tags, int depth)
-{
-	struct request **tag_index;
-	unsigned long *tag_map;
-	int nr_ulongs;
-
-	if (depth > q->nr_requests * 2) {
-		depth = q->nr_requests * 2;
-		printk(KERN_ERR "%s: adjusted depth to %d\n",
-				__FUNCTION__, depth);
-	}
-
-	tag_index = kmalloc(depth * sizeof(struct request *), GFP_ATOMIC);
-	if (!tag_index)
-		goto fail;
-
-	nr_ulongs = ALIGN(depth, BITS_PER_LONG) / BITS_PER_LONG;
-	tag_map = kmalloc(nr_ulongs * sizeof(unsigned long), GFP_ATOMIC);
-	if (!tag_map)
-		goto fail;
-
-	memset(tag_index, 0, depth * sizeof(struct request *));
-	memset(tag_map, 0, nr_ulongs * sizeof(unsigned long));
-	tags->real_max_depth = depth;
-	tags->max_depth = depth;
-	tags->tag_index = tag_index;
-	tags->tag_map = tag_map;
-
-	return 0;
-fail:
-	kfree(tag_index);
-	return -ENOMEM;
-}
-
-/**
- * blk_queue_init_tags - initialize the queue tag info
- * @q:  the request queue for the device
- * @depth:  the maximum queue depth supported
- * @tags: the tag to use
- **/
-int blk_queue_init_tags(request_queue_t *q, int depth,
-			struct blk_queue_tag *tags)
-{
-	int rc;
-
-	BUG_ON(tags && q->queue_tags && tags != q->queue_tags);
-
-	if (!tags && !q->queue_tags) {
-		tags = kmalloc(sizeof(struct blk_queue_tag), GFP_ATOMIC);
-		if (!tags)
-			goto fail;
-
-		if (init_tag_map(q, tags, depth))
-			goto fail;
-
-		INIT_LIST_HEAD(&tags->busy_list);
-		tags->busy = 0;
-		atomic_set(&tags->refcnt, 1);
-	} else if (q->queue_tags) {
-		if ((rc = blk_queue_resize_tags(q, depth)))
-			return rc;
-		set_bit(QUEUE_FLAG_QUEUED, &q->queue_flags);
-		return 0;
-	} else
-		atomic_inc(&tags->refcnt);
-
-	/*
-	 * assign it, all done
-	 */
-	q->queue_tags = tags;
-	q->queue_flags |= (1 << QUEUE_FLAG_QUEUED);
-	return 0;
-fail:
-	kfree(tags);
-	return -ENOMEM;
-}
-
-EXPORT_SYMBOL(blk_queue_init_tags);
-
-/**
- * blk_queue_resize_tags - change the queueing depth
- * @q:  the request queue for the device
- * @new_depth: the new max command queueing depth
- *
- *  Notes:
- *    Must be called with the queue lock held.
- **/
-int blk_queue_resize_tags(request_queue_t *q, int new_depth)
-{
-	struct blk_queue_tag *bqt = q->queue_tags;
-	struct request **tag_index;
-	unsigned long *tag_map;
-	int max_depth, nr_ulongs;
-
-	if (!bqt)
-		return -ENXIO;
-
-	/*
-	 * if we already have large enough real_max_depth.  just
-	 * adjust max_depth.  *NOTE* as requests with tag value
-	 * between new_depth and real_max_depth can be in-flight, tag
-	 * map can not be shrunk blindly here.
-	 */
-	if (new_depth <= bqt->real_max_depth) {
-		bqt->max_depth = new_depth;
-		return 0;
-	}
-
-	/*
-	 * save the old state info, so we can copy it back
-	 */
-	tag_index = bqt->tag_index;
-	tag_map = bqt->tag_map;
-	max_depth = bqt->real_max_depth;
-
-	if (init_tag_map(q, bqt, new_depth))
-		return -ENOMEM;
-
-	memcpy(bqt->tag_index, tag_index, max_depth * sizeof(struct request *));
-	nr_ulongs = ALIGN(max_depth, BITS_PER_LONG) / BITS_PER_LONG;
-	memcpy(bqt->tag_map, tag_map, nr_ulongs * sizeof(unsigned long));
-
-	kfree(tag_index);
-	kfree(tag_map);
-	return 0;
-}
-
-EXPORT_SYMBOL(blk_queue_resize_tags);
-
-/**
- * blk_queue_end_tag - end tag operations for a request
- * @q:  the request queue for the device
- * @rq: the request that has completed
- *
- *  Description:
- *    Typically called when end_that_request_first() returns 0, meaning
- *    all transfers have been done for a request. It's important to call
- *    this function before end_that_request_last(), as that will put the
- *    request back on the free list thus corrupting the internal tag list.
- *
- *  Notes:
- *   queue lock must be held.
- **/
-void blk_queue_end_tag(request_queue_t *q, struct request *rq)
-{
-	struct blk_queue_tag *bqt = q->queue_tags;
-	int tag = rq->tag;
-
-	BUG_ON(tag == -1);
-
-	if (unlikely(tag >= bqt->real_max_depth))
-		/*
-		 * This can happen after tag depth has been reduced.
-		 * FIXME: how about a warning or info message here?
-		 */
-		return;
-
-	if (unlikely(!__test_and_clear_bit(tag, bqt->tag_map))) {
-		printk(KERN_ERR "%s: attempt to clear non-busy tag (%d)\n",
-		       __FUNCTION__, tag);
-		return;
-	}
-
-	list_del_init(&rq->queuelist);
-	rq->flags &= ~REQ_QUEUED;
-	rq->tag = -1;
-
-	if (unlikely(bqt->tag_index[tag] == NULL))
-		printk(KERN_ERR "%s: tag %d is missing\n",
-		       __FUNCTION__, tag);
-
-	bqt->tag_index[tag] = NULL;
-	bqt->busy--;
-}
-
-EXPORT_SYMBOL(blk_queue_end_tag);
-
-/**
- * blk_queue_start_tag - find a free tag and assign it
- * @q:  the request queue for the device
- * @rq:  the block request that needs tagging
- *
- *  Description:
- *    This can either be used as a stand-alone helper, or possibly be
- *    assigned as the queue &prep_rq_fn (in which case &struct request
- *    automagically gets a tag assigned). Note that this function
- *    assumes that any type of request can be queued! if this is not
- *    true for your device, you must check the request type before
- *    calling this function.  The request will also be removed from
- *    the request queue, so it's the drivers responsibility to readd
- *    it if it should need to be restarted for some reason.
- *
- *  Notes:
- *   queue lock must be held.
- **/
-int blk_queue_start_tag(request_queue_t *q, struct request *rq)
-{
-	struct blk_queue_tag *bqt = q->queue_tags;
-	int tag;
-
-	if (unlikely((rq->flags & REQ_QUEUED))) {
-		printk(KERN_ERR 
-		       "%s: request %p for device [%s] already tagged %d",
-		       __FUNCTION__, rq,
-		       rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->tag);
-		BUG();
-	}
-
-	tag = find_first_zero_bit(bqt->tag_map, bqt->max_depth);
-	if (tag >= bqt->max_depth)
-		return 1;
-
-	__set_bit(tag, bqt->tag_map);
-
-	rq->flags |= REQ_QUEUED;
-	rq->tag = tag;
-	bqt->tag_index[tag] = rq;
-	blkdev_dequeue_request(rq);
-	list_add(&rq->queuelist, &bqt->busy_list);
-	bqt->busy++;
-	return 0;
-}
-
-EXPORT_SYMBOL(blk_queue_start_tag);
-
-/**
- * blk_queue_invalidate_tags - invalidate all pending tags
- * @q:  the request queue for the device
- *
- *  Description:
- *   Hardware conditions may dictate a need to stop all pending requests.
- *   In this case, we will safely clear the block side of the tag queue and
- *   readd all requests to the request queue in the right order.
- *
- *  Notes:
- *   queue lock must be held.
- **/
-void blk_queue_invalidate_tags(request_queue_t *q)
-{
-	struct blk_queue_tag *bqt = q->queue_tags;
-	struct list_head *tmp, *n;
-	struct request *rq;
-
-	list_for_each_safe(tmp, n, &bqt->busy_list) {
-		rq = list_entry_rq(tmp);
-
-		if (rq->tag == -1) {
-			printk(KERN_ERR
-			       "%s: bad tag found on list\n", __FUNCTION__);
-			list_del_init(&rq->queuelist);
-			rq->flags &= ~REQ_QUEUED;
-		} else
-			blk_queue_end_tag(q, rq);
-
-		rq->flags &= ~REQ_STARTED;
-		__elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0);
-	}
-}
-
-EXPORT_SYMBOL(blk_queue_invalidate_tags);
-
-static char *rq_flags[] = {
-	"REQ_RW",
-	"REQ_FAILFAST",
-	"REQ_SORTED",
-	"REQ_SOFTBARRIER",
-	"REQ_HARDBARRIER",
-	"REQ_CMD",
-	"REQ_NOMERGE",
-	"REQ_STARTED",
-	"REQ_DONTPREP",
-	"REQ_QUEUED",
-	"REQ_ELVPRIV",
-	"REQ_PC",
-	"REQ_BLOCK_PC",
-	"REQ_SENSE",
-	"REQ_FAILED",
-	"REQ_QUIET",
-	"REQ_SPECIAL",
-	"REQ_DRIVE_CMD",
-	"REQ_DRIVE_TASK",
-	"REQ_DRIVE_TASKFILE",
-	"REQ_PREEMPT",
-	"REQ_PM_SUSPEND",
-	"REQ_PM_RESUME",
-	"REQ_PM_SHUTDOWN",
-};
-
-void blk_dump_rq_flags(struct request *rq, char *msg)
-{
-	int bit;
-
-	printk("%s: dev %s: flags = ", msg,
-		rq->rq_disk ? rq->rq_disk->disk_name : "?");
-	bit = 0;
-	do {
-		if (rq->flags & (1 << bit))
-			printk("%s ", rq_flags[bit]);
-		bit++;
-	} while (bit < __REQ_NR_BITS);
-
-	printk("\nsector %llu, nr/cnr %lu/%u\n", (unsigned long long)rq->sector,
-						       rq->nr_sectors,
-						       rq->current_nr_sectors);
-	printk("bio %p, biotail %p, buffer %p, data %p, len %u\n", rq->bio, rq->biotail, rq->buffer, rq->data, rq->data_len);
-
-	if (rq->flags & (REQ_BLOCK_PC | REQ_PC)) {
-		printk("cdb: ");
-		for (bit = 0; bit < sizeof(rq->cmd); bit++)
-			printk("%02x ", rq->cmd[bit]);
-		printk("\n");
-	}
-}
-
-EXPORT_SYMBOL(blk_dump_rq_flags);
-
-void blk_recount_segments(request_queue_t *q, struct bio *bio)
-{
-	struct bio_vec *bv, *bvprv = NULL;
-	int i, nr_phys_segs, nr_hw_segs, seg_size, hw_seg_size, cluster;
-	int high, highprv = 1;
-
-	if (unlikely(!bio->bi_io_vec))
-		return;
-
-	cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
-	hw_seg_size = seg_size = nr_phys_segs = nr_hw_segs = 0;
-	bio_for_each_segment(bv, bio, i) {
-		/*
-		 * the trick here is making sure that a high page is never
-		 * considered part of another segment, since that might
-		 * change with the bounce page.
-		 */
-		high = page_to_pfn(bv->bv_page) >= q->bounce_pfn;
-		if (high || highprv)
-			goto new_hw_segment;
-		if (cluster) {
-			if (seg_size + bv->bv_len > q->max_segment_size)
-				goto new_segment;
-			if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
-				goto new_segment;
-			if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
-				goto new_segment;
-			if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len))
-				goto new_hw_segment;
-
-			seg_size += bv->bv_len;
-			hw_seg_size += bv->bv_len;
-			bvprv = bv;
-			continue;
-		}
-new_segment:
-		if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) &&
-		    !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len)) {
-			hw_seg_size += bv->bv_len;
-		} else {
-new_hw_segment:
-			if (hw_seg_size > bio->bi_hw_front_size)
-				bio->bi_hw_front_size = hw_seg_size;
-			hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len;
-			nr_hw_segs++;
-		}
-
-		nr_phys_segs++;
-		bvprv = bv;
-		seg_size = bv->bv_len;
-		highprv = high;
-	}
-	if (hw_seg_size > bio->bi_hw_back_size)
-		bio->bi_hw_back_size = hw_seg_size;
-	if (nr_hw_segs == 1 && hw_seg_size > bio->bi_hw_front_size)
-		bio->bi_hw_front_size = hw_seg_size;
-	bio->bi_phys_segments = nr_phys_segs;
-	bio->bi_hw_segments = nr_hw_segs;
-	bio->bi_flags |= (1 << BIO_SEG_VALID);
-}
-
-
-static int blk_phys_contig_segment(request_queue_t *q, struct bio *bio,
-				   struct bio *nxt)
-{
-	if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER)))
-		return 0;
-
-	if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)))
-		return 0;
-	if (bio->bi_size + nxt->bi_size > q->max_segment_size)
-		return 0;
-
-	/*
-	 * bio and nxt are contigous in memory, check if the queue allows
-	 * these two to be merged into one
-	 */
-	if (BIO_SEG_BOUNDARY(q, bio, nxt))
-		return 1;
-
-	return 0;
-}
-
-static int blk_hw_contig_segment(request_queue_t *q, struct bio *bio,
-				 struct bio *nxt)
-{
-	if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
-		blk_recount_segments(q, bio);
-	if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID)))
-		blk_recount_segments(q, nxt);
-	if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) ||
-	    BIOVEC_VIRT_OVERSIZE(bio->bi_hw_front_size + bio->bi_hw_back_size))
-		return 0;
-	if (bio->bi_size + nxt->bi_size > q->max_segment_size)
-		return 0;
-
-	return 1;
-}
-
-/*
- * map a request to scatterlist, return number of sg entries setup. Caller
- * must make sure sg can hold rq->nr_phys_segments entries
- */
-int blk_rq_map_sg(request_queue_t *q, struct request *rq, struct scatterlist *sg)
-{
-	struct bio_vec *bvec, *bvprv;
-	struct bio *bio;
-	int nsegs, i, cluster;
-
-	nsegs = 0;
-	cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
-
-	/*
-	 * for each bio in rq
-	 */
-	bvprv = NULL;
-	rq_for_each_bio(bio, rq) {
-		/*
-		 * for each segment in bio
-		 */
-		bio_for_each_segment(bvec, bio, i) {
-			int nbytes = bvec->bv_len;
-
-			if (bvprv && cluster) {
-				if (sg[nsegs - 1].length + nbytes > q->max_segment_size)
-					goto new_segment;
-
-				if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
-					goto new_segment;
-				if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
-					goto new_segment;
-
-				sg[nsegs - 1].length += nbytes;
-			} else {
-new_segment:
-				memset(&sg[nsegs],0,sizeof(struct scatterlist));
-				sg[nsegs].page = bvec->bv_page;
-				sg[nsegs].length = nbytes;
-				sg[nsegs].offset = bvec->bv_offset;
-
-				nsegs++;
-			}
-			bvprv = bvec;
-		} /* segments in bio */
-	} /* bios in rq */
-
-	return nsegs;
-}
-
-EXPORT_SYMBOL(blk_rq_map_sg);
-
-/*
- * the standard queue merge functions, can be overridden with device
- * specific ones if so desired
- */
-
-static inline int ll_new_mergeable(request_queue_t *q,
-				   struct request *req,
-				   struct bio *bio)
-{
-	int nr_phys_segs = bio_phys_segments(q, bio);
-
-	if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
-		req->flags |= REQ_NOMERGE;
-		if (req == q->last_merge)
-			q->last_merge = NULL;
-		return 0;
-	}
-
-	/*
-	 * A hw segment is just getting larger, bump just the phys
-	 * counter.
-	 */
-	req->nr_phys_segments += nr_phys_segs;
-	return 1;
-}
-
-static inline int ll_new_hw_segment(request_queue_t *q,
-				    struct request *req,
-				    struct bio *bio)
-{
-	int nr_hw_segs = bio_hw_segments(q, bio);
-	int nr_phys_segs = bio_phys_segments(q, bio);
-
-	if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments
-	    || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
-		req->flags |= REQ_NOMERGE;
-		if (req == q->last_merge)
-			q->last_merge = NULL;
-		return 0;
-	}
-
-	/*
-	 * This will form the start of a new hw segment.  Bump both
-	 * counters.
-	 */
-	req->nr_hw_segments += nr_hw_segs;
-	req->nr_phys_segments += nr_phys_segs;
-	return 1;
-}
-
-static int ll_back_merge_fn(request_queue_t *q, struct request *req, 
-			    struct bio *bio)
-{
-	int len;
-
-	if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
-		req->flags |= REQ_NOMERGE;
-		if (req == q->last_merge)
-			q->last_merge = NULL;
-		return 0;
-	}
-	if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID)))
-		blk_recount_segments(q, req->biotail);
-	if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
-		blk_recount_segments(q, bio);
-	len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size;
-	if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) &&
-	    !BIOVEC_VIRT_OVERSIZE(len)) {
-		int mergeable =  ll_new_mergeable(q, req, bio);
-
-		if (mergeable) {
-			if (req->nr_hw_segments == 1)
-				req->bio->bi_hw_front_size = len;
-			if (bio->bi_hw_segments == 1)
-				bio->bi_hw_back_size = len;
-		}
-		return mergeable;
-	}
-
-	return ll_new_hw_segment(q, req, bio);
-}
-
-static int ll_front_merge_fn(request_queue_t *q, struct request *req, 
-			     struct bio *bio)
-{
-	int len;
-
-	if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
-		req->flags |= REQ_NOMERGE;
-		if (req == q->last_merge)
-			q->last_merge = NULL;
-		return 0;
-	}
-	len = bio->bi_hw_back_size + req->bio->bi_hw_front_size;
-	if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
-		blk_recount_segments(q, bio);
-	if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID)))
-		blk_recount_segments(q, req->bio);
-	if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) &&
-	    !BIOVEC_VIRT_OVERSIZE(len)) {
-		int mergeable =  ll_new_mergeable(q, req, bio);
-
-		if (mergeable) {
-			if (bio->bi_hw_segments == 1)
-				bio->bi_hw_front_size = len;
-			if (req->nr_hw_segments == 1)
-				req->biotail->bi_hw_back_size = len;
-		}
-		return mergeable;
-	}
-
-	return ll_new_hw_segment(q, req, bio);
-}
-
-static int ll_merge_requests_fn(request_queue_t *q, struct request *req,
-				struct request *next)
-{
-	int total_phys_segments;
-	int total_hw_segments;
-
-	/*
-	 * First check if the either of the requests are re-queued
-	 * requests.  Can't merge them if they are.
-	 */
-	if (req->special || next->special)
-		return 0;
-
-	/*
-	 * Will it become too large?
-	 */
-	if ((req->nr_sectors + next->nr_sectors) > q->max_sectors)
-		return 0;
-
-	total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
-	if (blk_phys_contig_segment(q, req->biotail, next->bio))
-		total_phys_segments--;
-
-	if (total_phys_segments > q->max_phys_segments)
-		return 0;
-
-	total_hw_segments = req->nr_hw_segments + next->nr_hw_segments;
-	if (blk_hw_contig_segment(q, req->biotail, next->bio)) {
-		int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size;
-		/*
-		 * propagate the combined length to the end of the requests
-		 */
-		if (req->nr_hw_segments == 1)
-			req->bio->bi_hw_front_size = len;
-		if (next->nr_hw_segments == 1)
-			next->biotail->bi_hw_back_size = len;
-		total_hw_segments--;
-	}
-
-	if (total_hw_segments > q->max_hw_segments)
-		return 0;
-
-	/* Merge is OK... */
-	req->nr_phys_segments = total_phys_segments;
-	req->nr_hw_segments = total_hw_segments;
-	return 1;
-}
-
-/*
- * "plug" the device if there are no outstanding requests: this will
- * force the transfer to start only after we have put all the requests
- * on the list.
- *
- * This is called with interrupts off and no requests on the queue and
- * with the queue lock held.
- */
-void blk_plug_device(request_queue_t *q)
-{
-	WARN_ON(!irqs_disabled());
-
-	/*
-	 * don't plug a stopped queue, it must be paired with blk_start_queue()
-	 * which will restart the queueing
-	 */
-	if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags))
-		return;
-
-	if (!test_and_set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
-		mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
-}
-
-EXPORT_SYMBOL(blk_plug_device);
-
-/*
- * remove the queue from the plugged list, if present. called with
- * queue lock held and interrupts disabled.
- */
-int blk_remove_plug(request_queue_t *q)
-{
-	WARN_ON(!irqs_disabled());
-
-	if (!test_and_clear_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
-		return 0;
-
-	del_timer(&q->unplug_timer);
-	return 1;
-}
-
-EXPORT_SYMBOL(blk_remove_plug);
-
-/*
- * remove the plug and let it rip..
- */
-void __generic_unplug_device(request_queue_t *q)
-{
-	if (unlikely(test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)))
-		return;
-
-	if (!blk_remove_plug(q))
-		return;
-
-	q->request_fn(q);
-}
-EXPORT_SYMBOL(__generic_unplug_device);
-
-/**
- * generic_unplug_device - fire a request queue
- * @q:    The &request_queue_t in question
- *
- * Description:
- *   Linux uses plugging to build bigger requests queues before letting
- *   the device have at them. If a queue is plugged, the I/O scheduler
- *   is still adding and merging requests on the queue. Once the queue
- *   gets unplugged, the request_fn defined for the queue is invoked and
- *   transfers started.
- **/
-void generic_unplug_device(request_queue_t *q)
-{
-	spin_lock_irq(q->queue_lock);
-	__generic_unplug_device(q);
-	spin_unlock_irq(q->queue_lock);
-}
-EXPORT_SYMBOL(generic_unplug_device);
-
-static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
-				   struct page *page)
-{
-	request_queue_t *q = bdi->unplug_io_data;
-
-	/*
-	 * devices don't necessarily have an ->unplug_fn defined
-	 */
-	if (q->unplug_fn)
-		q->unplug_fn(q);
-}
-
-static void blk_unplug_work(void *data)
-{
-	request_queue_t *q = data;
-
-	q->unplug_fn(q);
-}
-
-static void blk_unplug_timeout(unsigned long data)
-{
-	request_queue_t *q = (request_queue_t *)data;
-
-	kblockd_schedule_work(&q->unplug_work);
-}
-
-/**
- * blk_start_queue - restart a previously stopped queue
- * @q:    The &request_queue_t in question
- *
- * Description:
- *   blk_start_queue() will clear the stop flag on the queue, and call
- *   the request_fn for the queue if it was in a stopped state when
- *   entered. Also see blk_stop_queue(). Queue lock must be held.
- **/
-void blk_start_queue(request_queue_t *q)
-{
-	clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
-
-	/*
-	 * one level of recursion is ok and is much faster than kicking
-	 * the unplug handling
-	 */
-	if (!test_and_set_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) {
-		q->request_fn(q);
-		clear_bit(QUEUE_FLAG_REENTER, &q->queue_flags);
-	} else {
-		blk_plug_device(q);
-		kblockd_schedule_work(&q->unplug_work);
-	}
-}
-
-EXPORT_SYMBOL(blk_start_queue);
-
-/**
- * blk_stop_queue - stop a queue
- * @q:    The &request_queue_t in question
- *
- * Description:
- *   The Linux block layer assumes that a block driver will consume all
- *   entries on the request queue when the request_fn strategy is called.
- *   Often this will not happen, because of hardware limitations (queue
- *   depth settings). If a device driver gets a 'queue full' response,
- *   or if it simply chooses not to queue more I/O at one point, it can
- *   call this function to prevent the request_fn from being called until
- *   the driver has signalled it's ready to go again. This happens by calling
- *   blk_start_queue() to restart queue operations. Queue lock must be held.
- **/
-void blk_stop_queue(request_queue_t *q)
-{
-	blk_remove_plug(q);
-	set_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
-}
-EXPORT_SYMBOL(blk_stop_queue);
-
-/**
- * blk_sync_queue - cancel any pending callbacks on a queue
- * @q: the queue
- *
- * Description:
- *     The block layer may perform asynchronous callback activity
- *     on a queue, such as calling the unplug function after a timeout.
- *     A block device may call blk_sync_queue to ensure that any
- *     such activity is cancelled, thus allowing it to release resources
- *     the the callbacks might use. The caller must already have made sure
- *     that its ->make_request_fn will not re-add plugging prior to calling
- *     this function.
- *
- */
-void blk_sync_queue(struct request_queue *q)
-{
-	del_timer_sync(&q->unplug_timer);
-	kblockd_flush();
-}
-EXPORT_SYMBOL(blk_sync_queue);
-
-/**
- * blk_run_queue - run a single device queue
- * @q:	The queue to run
- */
-void blk_run_queue(struct request_queue *q)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	blk_remove_plug(q);
-	if (!elv_queue_empty(q))
-		q->request_fn(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-EXPORT_SYMBOL(blk_run_queue);
-
-/**
- * blk_cleanup_queue: - release a &request_queue_t when it is no longer needed
- * @q:    the request queue to be released
- *
- * Description:
- *     blk_cleanup_queue is the pair to blk_init_queue() or
- *     blk_queue_make_request().  It should be called when a request queue is
- *     being released; typically when a block device is being de-registered.
- *     Currently, its primary task it to free all the &struct request
- *     structures that were allocated to the queue and the queue itself.
- *
- * Caveat:
- *     Hopefully the low level driver will have finished any
- *     outstanding requests first...
- **/
-void blk_cleanup_queue(request_queue_t * q)
-{
-	struct request_list *rl = &q->rq;
-
-	if (!atomic_dec_and_test(&q->refcnt))
-		return;
-
-	if (q->elevator)
-		elevator_exit(q->elevator);
-
-	blk_sync_queue(q);
-
-	if (rl->rq_pool)
-		mempool_destroy(rl->rq_pool);
-
-	if (q->queue_tags)
-		__blk_queue_free_tags(q);
-
-	blk_queue_ordered(q, QUEUE_ORDERED_NONE);
-
-	kmem_cache_free(requestq_cachep, q);
-}
-
-EXPORT_SYMBOL(blk_cleanup_queue);
-
-static int blk_init_free_list(request_queue_t *q)
-{
-	struct request_list *rl = &q->rq;
-
-	rl->count[READ] = rl->count[WRITE] = 0;
-	rl->starved[READ] = rl->starved[WRITE] = 0;
-	rl->elvpriv = 0;
-	init_waitqueue_head(&rl->wait[READ]);
-	init_waitqueue_head(&rl->wait[WRITE]);
-
-	rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
-				mempool_free_slab, request_cachep, q->node);
-
-	if (!rl->rq_pool)
-		return -ENOMEM;
-
-	return 0;
-}
-
-static int __make_request(request_queue_t *, struct bio *);
-
-request_queue_t *blk_alloc_queue(gfp_t gfp_mask)
-{
-	return blk_alloc_queue_node(gfp_mask, -1);
-}
-EXPORT_SYMBOL(blk_alloc_queue);
-
-request_queue_t *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
-{
-	request_queue_t *q;
-
-	q = kmem_cache_alloc_node(requestq_cachep, gfp_mask, node_id);
-	if (!q)
-		return NULL;
-
-	memset(q, 0, sizeof(*q));
-	init_timer(&q->unplug_timer);
-	atomic_set(&q->refcnt, 1);
-
-	q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug;
-	q->backing_dev_info.unplug_io_data = q;
-
-	return q;
-}
-EXPORT_SYMBOL(blk_alloc_queue_node);
-
-/**
- * blk_init_queue  - prepare a request queue for use with a block device
- * @rfn:  The function to be called to process requests that have been
- *        placed on the queue.
- * @lock: Request queue spin lock
- *
- * Description:
- *    If a block device wishes to use the standard request handling procedures,
- *    which sorts requests and coalesces adjacent requests, then it must
- *    call blk_init_queue().  The function @rfn will be called when there
- *    are requests on the queue that need to be processed.  If the device
- *    supports plugging, then @rfn may not be called immediately when requests
- *    are available on the queue, but may be called at some time later instead.
- *    Plugged queues are generally unplugged when a buffer belonging to one
- *    of the requests on the queue is needed, or due to memory pressure.
- *
- *    @rfn is not required, or even expected, to remove all requests off the
- *    queue, but only as many as it can handle at a time.  If it does leave
- *    requests on the queue, it is responsible for arranging that the requests
- *    get dealt with eventually.
- *
- *    The queue spin lock must be held while manipulating the requests on the
- *    request queue.
- *
- *    Function returns a pointer to the initialized request queue, or NULL if
- *    it didn't succeed.
- *
- * Note:
- *    blk_init_queue() must be paired with a blk_cleanup_queue() call
- *    when the block device is deactivated (such as at module unload).
- **/
-
-request_queue_t *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
-{
-	return blk_init_queue_node(rfn, lock, -1);
-}
-EXPORT_SYMBOL(blk_init_queue);
-
-request_queue_t *
-blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
-{
-	request_queue_t *q = blk_alloc_queue_node(GFP_KERNEL, node_id);
-
-	if (!q)
-		return NULL;
-
-	q->node = node_id;
-	if (blk_init_free_list(q))
-		goto out_init;
-
-	/*
-	 * if caller didn't supply a lock, they get per-queue locking with
-	 * our embedded lock
-	 */
-	if (!lock) {
-		spin_lock_init(&q->__queue_lock);
-		lock = &q->__queue_lock;
-	}
-
-	q->request_fn		= rfn;
-	q->back_merge_fn       	= ll_back_merge_fn;
-	q->front_merge_fn      	= ll_front_merge_fn;
-	q->merge_requests_fn	= ll_merge_requests_fn;
-	q->prep_rq_fn		= NULL;
-	q->unplug_fn		= generic_unplug_device;
-	q->queue_flags		= (1 << QUEUE_FLAG_CLUSTER);
-	q->queue_lock		= lock;
-
-	blk_queue_segment_boundary(q, 0xffffffff);
-
-	blk_queue_make_request(q, __make_request);
-	blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE);
-
-	blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
-	blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
-
-	/*
-	 * all done
-	 */
-	if (!elevator_init(q, NULL)) {
-		blk_queue_congestion_threshold(q);
-		return q;
-	}
-
-	blk_cleanup_queue(q);
-out_init:
-	kmem_cache_free(requestq_cachep, q);
-	return NULL;
-}
-EXPORT_SYMBOL(blk_init_queue_node);
-
-int blk_get_queue(request_queue_t *q)
-{
-	if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
-		atomic_inc(&q->refcnt);
-		return 0;
-	}
-
-	return 1;
-}
-
-EXPORT_SYMBOL(blk_get_queue);
-
-static inline void blk_free_request(request_queue_t *q, struct request *rq)
-{
-	if (rq->flags & REQ_ELVPRIV)
-		elv_put_request(q, rq);
-	mempool_free(rq, q->rq.rq_pool);
-}
-
-static inline struct request *
-blk_alloc_request(request_queue_t *q, int rw, struct bio *bio,
-		  int priv, gfp_t gfp_mask)
-{
-	struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
-
-	if (!rq)
-		return NULL;
-
-	/*
-	 * first three bits are identical in rq->flags and bio->bi_rw,
-	 * see bio.h and blkdev.h
-	 */
-	rq->flags = rw;
-
-	if (priv) {
-		if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) {
-			mempool_free(rq, q->rq.rq_pool);
-			return NULL;
-		}
-		rq->flags |= REQ_ELVPRIV;
-	}
-
-	return rq;
-}
-
-/*
- * ioc_batching returns true if the ioc is a valid batching request and
- * should be given priority access to a request.
- */
-static inline int ioc_batching(request_queue_t *q, struct io_context *ioc)
-{
-	if (!ioc)
-		return 0;
-
-	/*
-	 * Make sure the process is able to allocate at least 1 request
-	 * even if the batch times out, otherwise we could theoretically
-	 * lose wakeups.
-	 */
-	return ioc->nr_batch_requests == q->nr_batching ||
-		(ioc->nr_batch_requests > 0
-		&& time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME));
-}
-
-/*
- * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
- * will cause the process to be a "batcher" on all queues in the system. This
- * is the behaviour we want though - once it gets a wakeup it should be given
- * a nice run.
- */
-static void ioc_set_batching(request_queue_t *q, struct io_context *ioc)
-{
-	if (!ioc || ioc_batching(q, ioc))
-		return;
-
-	ioc->nr_batch_requests = q->nr_batching;
-	ioc->last_waited = jiffies;
-}
-
-static void __freed_request(request_queue_t *q, int rw)
-{
-	struct request_list *rl = &q->rq;
-
-	if (rl->count[rw] < queue_congestion_off_threshold(q))
-		clear_queue_congested(q, rw);
-
-	if (rl->count[rw] + 1 <= q->nr_requests) {
-		if (waitqueue_active(&rl->wait[rw]))
-			wake_up(&rl->wait[rw]);
-
-		blk_clear_queue_full(q, rw);
-	}
-}
-
-/*
- * A request has just been released.  Account for it, update the full and
- * congestion status, wake up any waiters.   Called under q->queue_lock.
- */
-static void freed_request(request_queue_t *q, int rw, int priv)
-{
-	struct request_list *rl = &q->rq;
-
-	rl->count[rw]--;
-	if (priv)
-		rl->elvpriv--;
-
-	__freed_request(q, rw);
-
-	if (unlikely(rl->starved[rw ^ 1]))
-		__freed_request(q, rw ^ 1);
-}
-
-#define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist)
-/*
- * Get a free request, queue_lock must be held.
- * Returns NULL on failure, with queue_lock held.
- * Returns !NULL on success, with queue_lock *not held*.
- */
-static struct request *get_request(request_queue_t *q, int rw, struct bio *bio,
-				   gfp_t gfp_mask)
-{
-	struct request *rq = NULL;
-	struct request_list *rl = &q->rq;
-	struct io_context *ioc = current_io_context(GFP_ATOMIC);
-	int priv;
-
-	if (rl->count[rw]+1 >= q->nr_requests) {
-		/*
-		 * The queue will fill after this allocation, so set it as
-		 * full, and mark this process as "batching". This process
-		 * will be allowed to complete a batch of requests, others
-		 * will be blocked.
-		 */
-		if (!blk_queue_full(q, rw)) {
-			ioc_set_batching(q, ioc);
-			blk_set_queue_full(q, rw);
-		}
-	}
-
-	switch (elv_may_queue(q, rw, bio)) {
-		case ELV_MQUEUE_NO:
-			goto rq_starved;
-		case ELV_MQUEUE_MAY:
-			break;
-		case ELV_MQUEUE_MUST:
-			goto get_rq;
-	}
-
-	if (blk_queue_full(q, rw) && !ioc_batching(q, ioc)) {
-		/*
-		 * The queue is full and the allocating process is not a
-		 * "batcher", and not exempted by the IO scheduler
-		 */
-		goto out;
-	}
-
-get_rq:
-	/*
-	 * Only allow batching queuers to allocate up to 50% over the defined
-	 * limit of requests, otherwise we could have thousands of requests
-	 * allocated with any setting of ->nr_requests
-	 */
-	if (rl->count[rw] >= (3 * q->nr_requests / 2))
-		goto out;
-
-	rl->count[rw]++;
-	rl->starved[rw] = 0;
-	if (rl->count[rw] >= queue_congestion_on_threshold(q))
-		set_queue_congested(q, rw);
-
-	priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
-	if (priv)
-		rl->elvpriv++;
-
-	spin_unlock_irq(q->queue_lock);
-
-	rq = blk_alloc_request(q, rw, bio, priv, gfp_mask);
-	if (!rq) {
-		/*
-		 * Allocation failed presumably due to memory. Undo anything
-		 * we might have messed up.
-		 *
-		 * Allocating task should really be put onto the front of the
-		 * wait queue, but this is pretty rare.
-		 */
-		spin_lock_irq(q->queue_lock);
-		freed_request(q, rw, priv);
-
-		/*
-		 * in the very unlikely event that allocation failed and no
-		 * requests for this direction was pending, mark us starved
-		 * so that freeing of a request in the other direction will
-		 * notice us. another possible fix would be to split the
-		 * rq mempool into READ and WRITE
-		 */
-rq_starved:
-		if (unlikely(rl->count[rw] == 0))
-			rl->starved[rw] = 1;
-
-		goto out;
-	}
-
-	if (ioc_batching(q, ioc))
-		ioc->nr_batch_requests--;
-	
-	rq_init(q, rq);
-	rq->rl = rl;
-out:
-	return rq;
-}
-
-/*
- * No available requests for this queue, unplug the device and wait for some
- * requests to become available.
- *
- * Called with q->queue_lock held, and returns with it unlocked.
- */
-static struct request *get_request_wait(request_queue_t *q, int rw,
-					struct bio *bio)
-{
-	struct request *rq;
-
-	rq = get_request(q, rw, bio, GFP_NOIO);
-	while (!rq) {
-		DEFINE_WAIT(wait);
-		struct request_list *rl = &q->rq;
-
-		prepare_to_wait_exclusive(&rl->wait[rw], &wait,
-				TASK_UNINTERRUPTIBLE);
-
-		rq = get_request(q, rw, bio, GFP_NOIO);
-
-		if (!rq) {
-			struct io_context *ioc;
-
-			__generic_unplug_device(q);
-			spin_unlock_irq(q->queue_lock);
-			io_schedule();
-
-			/*
-			 * After sleeping, we become a "batching" process and
-			 * will be able to allocate at least one request, and
-			 * up to a big batch of them for a small period time.
-			 * See ioc_batching, ioc_set_batching
-			 */
-			ioc = current_io_context(GFP_NOIO);
-			ioc_set_batching(q, ioc);
-
-			spin_lock_irq(q->queue_lock);
-		}
-		finish_wait(&rl->wait[rw], &wait);
-	}
-
-	return rq;
-}
-
-struct request *blk_get_request(request_queue_t *q, int rw, gfp_t gfp_mask)
-{
-	struct request *rq;
-
-	BUG_ON(rw != READ && rw != WRITE);
-
-	spin_lock_irq(q->queue_lock);
-	if (gfp_mask & __GFP_WAIT) {
-		rq = get_request_wait(q, rw, NULL);
-	} else {
-		rq = get_request(q, rw, NULL, gfp_mask);
-		if (!rq)
-			spin_unlock_irq(q->queue_lock);
-	}
-	/* q->queue_lock is unlocked at this point */
-
-	return rq;
-}
-EXPORT_SYMBOL(blk_get_request);
-
-/**
- * blk_requeue_request - put a request back on queue
- * @q:		request queue where request should be inserted
- * @rq:		request to be inserted
- *
- * Description:
- *    Drivers often keep queueing requests until the hardware cannot accept
- *    more, when that condition happens we need to put the request back
- *    on the queue. Must be called with queue lock held.
- */
-void blk_requeue_request(request_queue_t *q, struct request *rq)
-{
-	if (blk_rq_tagged(rq))
-		blk_queue_end_tag(q, rq);
-
-	elv_requeue_request(q, rq);
-}
-
-EXPORT_SYMBOL(blk_requeue_request);
-
-/**
- * blk_insert_request - insert a special request in to a request queue
- * @q:		request queue where request should be inserted
- * @rq:		request to be inserted
- * @at_head:	insert request at head or tail of queue
- * @data:	private data
- *
- * Description:
- *    Many block devices need to execute commands asynchronously, so they don't
- *    block the whole kernel from preemption during request execution.  This is
- *    accomplished normally by inserting aritficial requests tagged as
- *    REQ_SPECIAL in to the corresponding request queue, and letting them be
- *    scheduled for actual execution by the request queue.
- *
- *    We have the option of inserting the head or the tail of the queue.
- *    Typically we use the tail for new ioctls and so forth.  We use the head
- *    of the queue for things like a QUEUE_FULL message from a device, or a
- *    host that is unable to accept a particular command.
- */
-void blk_insert_request(request_queue_t *q, struct request *rq,
-			int at_head, void *data)
-{
-	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
-	unsigned long flags;
-
-	/*
-	 * tell I/O scheduler that this isn't a regular read/write (ie it
-	 * must not attempt merges on this) and that it acts as a soft
-	 * barrier
-	 */
-	rq->flags |= REQ_SPECIAL | REQ_SOFTBARRIER;
-
-	rq->special = data;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-
-	/*
-	 * If command is tagged, release the tag
-	 */
-	if (blk_rq_tagged(rq))
-		blk_queue_end_tag(q, rq);
-
-	drive_stat_acct(rq, rq->nr_sectors, 1);
-	__elv_add_request(q, rq, where, 0);
-
-	if (blk_queue_plugged(q))
-		__generic_unplug_device(q);
-	else
-		q->request_fn(q);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-EXPORT_SYMBOL(blk_insert_request);
-
-/**
- * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
- * @q:		request queue where request should be inserted
- * @rq:		request structure to fill
- * @ubuf:	the user buffer
- * @len:	length of user data
- *
- * Description:
- *    Data will be mapped directly for zero copy io, if possible. Otherwise
- *    a kernel bounce buffer is used.
- *
- *    A matching blk_rq_unmap_user() must be issued at the end of io, while
- *    still in process context.
- *
- *    Note: The mapped bio may need to be bounced through blk_queue_bounce()
- *    before being submitted to the device, as pages mapped may be out of
- *    reach. It's the callers responsibility to make sure this happens. The
- *    original bio must be passed back in to blk_rq_unmap_user() for proper
- *    unmapping.
- */
-int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
-		    unsigned int len)
-{
-	unsigned long uaddr;
-	struct bio *bio;
-	int reading;
-
-	if (len > (q->max_sectors << 9))
-		return -EINVAL;
-	if (!len || !ubuf)
-		return -EINVAL;
-
-	reading = rq_data_dir(rq) == READ;
-
-	/*
-	 * if alignment requirement is satisfied, map in user pages for
-	 * direct dma. else, set up kernel bounce buffers
-	 */
-	uaddr = (unsigned long) ubuf;
-	if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
-		bio = bio_map_user(q, NULL, uaddr, len, reading);
-	else
-		bio = bio_copy_user(q, uaddr, len, reading);
-
-	if (!IS_ERR(bio)) {
-		rq->bio = rq->biotail = bio;
-		blk_rq_bio_prep(q, rq, bio);
-
-		rq->buffer = rq->data = NULL;
-		rq->data_len = len;
-		return 0;
-	}
-
-	/*
-	 * bio is the err-ptr
-	 */
-	return PTR_ERR(bio);
-}
-
-EXPORT_SYMBOL(blk_rq_map_user);
-
-/**
- * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
- * @q:		request queue where request should be inserted
- * @rq:		request to map data to
- * @iov:	pointer to the iovec
- * @iov_count:	number of elements in the iovec
- *
- * Description:
- *    Data will be mapped directly for zero copy io, if possible. Otherwise
- *    a kernel bounce buffer is used.
- *
- *    A matching blk_rq_unmap_user() must be issued at the end of io, while
- *    still in process context.
- *
- *    Note: The mapped bio may need to be bounced through blk_queue_bounce()
- *    before being submitted to the device, as pages mapped may be out of
- *    reach. It's the callers responsibility to make sure this happens. The
- *    original bio must be passed back in to blk_rq_unmap_user() for proper
- *    unmapping.
- */
-int blk_rq_map_user_iov(request_queue_t *q, struct request *rq,
-			struct sg_iovec *iov, int iov_count)
-{
-	struct bio *bio;
-
-	if (!iov || iov_count <= 0)
-		return -EINVAL;
-
-	/* we don't allow misaligned data like bio_map_user() does.  If the
-	 * user is using sg, they're expected to know the alignment constraints
-	 * and respect them accordingly */
-	bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
-	if (IS_ERR(bio))
-		return PTR_ERR(bio);
-
-	rq->bio = rq->biotail = bio;
-	blk_rq_bio_prep(q, rq, bio);
-	rq->buffer = rq->data = NULL;
-	rq->data_len = bio->bi_size;
-	return 0;
-}
-
-EXPORT_SYMBOL(blk_rq_map_user_iov);
-
-/**
- * blk_rq_unmap_user - unmap a request with user data
- * @bio:	bio to be unmapped
- * @ulen:	length of user buffer
- *
- * Description:
- *    Unmap a bio previously mapped by blk_rq_map_user().
- */
-int blk_rq_unmap_user(struct bio *bio, unsigned int ulen)
-{
-	int ret = 0;
-
-	if (bio) {
-		if (bio_flagged(bio, BIO_USER_MAPPED))
-			bio_unmap_user(bio);
-		else
-			ret = bio_uncopy_user(bio);
-	}
-
-	return 0;
-}
-
-EXPORT_SYMBOL(blk_rq_unmap_user);
-
-/**
- * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
- * @q:		request queue where request should be inserted
- * @rq:		request to fill
- * @kbuf:	the kernel buffer
- * @len:	length of user data
- * @gfp_mask:	memory allocation flags
- */
-int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf,
-		    unsigned int len, gfp_t gfp_mask)
-{
-	struct bio *bio;
-
-	if (len > (q->max_sectors << 9))
-		return -EINVAL;
-	if (!len || !kbuf)
-		return -EINVAL;
-
-	bio = bio_map_kern(q, kbuf, len, gfp_mask);
-	if (IS_ERR(bio))
-		return PTR_ERR(bio);
-
-	if (rq_data_dir(rq) == WRITE)
-		bio->bi_rw |= (1 << BIO_RW);
-
-	rq->bio = rq->biotail = bio;
-	blk_rq_bio_prep(q, rq, bio);
-
-	rq->buffer = rq->data = NULL;
-	rq->data_len = len;
-	return 0;
-}
-
-EXPORT_SYMBOL(blk_rq_map_kern);
-
-/**
- * blk_execute_rq_nowait - insert a request into queue for execution
- * @q:		queue to insert the request in
- * @bd_disk:	matching gendisk
- * @rq:		request to insert
- * @at_head:    insert request at head or tail of queue
- * @done:	I/O completion handler
- *
- * Description:
- *    Insert a fully prepared request at the back of the io scheduler queue
- *    for execution.  Don't wait for completion.
- */
-void blk_execute_rq_nowait(request_queue_t *q, struct gendisk *bd_disk,
-			   struct request *rq, int at_head,
-			   void (*done)(struct request *))
-{
-	int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
-
-	rq->rq_disk = bd_disk;
-	rq->flags |= REQ_NOMERGE;
-	rq->end_io = done;
-	elv_add_request(q, rq, where, 1);
-	generic_unplug_device(q);
-}
-
-/**
- * blk_execute_rq - insert a request into queue for execution
- * @q:		queue to insert the request in
- * @bd_disk:	matching gendisk
- * @rq:		request to insert
- * @at_head:    insert request at head or tail of queue
- *
- * Description:
- *    Insert a fully prepared request at the back of the io scheduler queue
- *    for execution and wait for completion.
- */
-int blk_execute_rq(request_queue_t *q, struct gendisk *bd_disk,
-		   struct request *rq, int at_head)
-{
-	DECLARE_COMPLETION(wait);
-	char sense[SCSI_SENSE_BUFFERSIZE];
-	int err = 0;
-
-	/*
-	 * we need an extra reference to the request, so we can look at
-	 * it after io completion
-	 */
-	rq->ref_count++;
-
-	if (!rq->sense) {
-		memset(sense, 0, sizeof(sense));
-		rq->sense = sense;
-		rq->sense_len = 0;
-	}
-
-	rq->waiting = &wait;
-	blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
-	wait_for_completion(&wait);
-	rq->waiting = NULL;
-
-	if (rq->errors)
-		err = -EIO;
-
-	return err;
-}
-
-EXPORT_SYMBOL(blk_execute_rq);
-
-/**
- * blkdev_issue_flush - queue a flush
- * @bdev:	blockdev to issue flush for
- * @error_sector:	error sector
- *
- * Description:
- *    Issue a flush for the block device in question. Caller can supply
- *    room for storing the error offset in case of a flush error, if they
- *    wish to.  Caller must run wait_for_completion() on its own.
- */
-int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
-{
-	request_queue_t *q;
-
-	if (bdev->bd_disk == NULL)
-		return -ENXIO;
-
-	q = bdev_get_queue(bdev);
-	if (!q)
-		return -ENXIO;
-	if (!q->issue_flush_fn)
-		return -EOPNOTSUPP;
-
-	return q->issue_flush_fn(q, bdev->bd_disk, error_sector);
-}
-
-EXPORT_SYMBOL(blkdev_issue_flush);
-
-static void drive_stat_acct(struct request *rq, int nr_sectors, int new_io)
-{
-	int rw = rq_data_dir(rq);
-
-	if (!blk_fs_request(rq) || !rq->rq_disk)
-		return;
-
-	if (!new_io) {
-		__disk_stat_inc(rq->rq_disk, merges[rw]);
-	} else {
-		disk_round_stats(rq->rq_disk);
-		rq->rq_disk->in_flight++;
-	}
-}
-
-/*
- * add-request adds a request to the linked list.
- * queue lock is held and interrupts disabled, as we muck with the
- * request queue list.
- */
-static inline void add_request(request_queue_t * q, struct request * req)
-{
-	drive_stat_acct(req, req->nr_sectors, 1);
-
-	if (q->activity_fn)
-		q->activity_fn(q->activity_data, rq_data_dir(req));
-
-	/*
-	 * elevator indicated where it wants this request to be
-	 * inserted at elevator_merge time
-	 */
-	__elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0);
-}
- 
-/*
- * disk_round_stats()	- Round off the performance stats on a struct
- * disk_stats.
- *
- * The average IO queue length and utilisation statistics are maintained
- * by observing the current state of the queue length and the amount of
- * time it has been in this state for.
- *
- * Normally, that accounting is done on IO completion, but that can result
- * in more than a second's worth of IO being accounted for within any one
- * second, leading to >100% utilisation.  To deal with that, we call this
- * function to do a round-off before returning the results when reading
- * /proc/diskstats.  This accounts immediately for all queue usage up to
- * the current jiffies and restarts the counters again.
- */
-void disk_round_stats(struct gendisk *disk)
-{
-	unsigned long now = jiffies;
-
-	if (now == disk->stamp)
-		return;
-
-	if (disk->in_flight) {
-		__disk_stat_add(disk, time_in_queue,
-				disk->in_flight * (now - disk->stamp));
-		__disk_stat_add(disk, io_ticks, (now - disk->stamp));
-	}
-	disk->stamp = now;
-}
-
-/*
- * queue lock must be held
- */
-static void __blk_put_request(request_queue_t *q, struct request *req)
-{
-	struct request_list *rl = req->rl;
-
-	if (unlikely(!q))
-		return;
-	if (unlikely(--req->ref_count))
-		return;
-
-	elv_completed_request(q, req);
-
-	req->rq_status = RQ_INACTIVE;
-	req->rl = NULL;
-
-	/*
-	 * Request may not have originated from ll_rw_blk. if not,
-	 * it didn't come out of our reserved rq pools
-	 */
-	if (rl) {
-		int rw = rq_data_dir(req);
-		int priv = req->flags & REQ_ELVPRIV;
-
-		BUG_ON(!list_empty(&req->queuelist));
-
-		blk_free_request(q, req);
-		freed_request(q, rw, priv);
-	}
-}
-
-void blk_put_request(struct request *req)
-{
-	unsigned long flags;
-	request_queue_t *q = req->q;
-
-	/*
-	 * Gee, IDE calls in w/ NULL q.  Fix IDE and remove the
-	 * following if (q) test.
-	 */
-	if (q) {
-		spin_lock_irqsave(q->queue_lock, flags);
-		__blk_put_request(q, req);
-		spin_unlock_irqrestore(q->queue_lock, flags);
-	}
-}
-
-EXPORT_SYMBOL(blk_put_request);
-
-/**
- * blk_end_sync_rq - executes a completion event on a request
- * @rq: request to complete
- */
-void blk_end_sync_rq(struct request *rq)
-{
-	struct completion *waiting = rq->waiting;
-
-	rq->waiting = NULL;
-	__blk_put_request(rq->q, rq);
-
-	/*
-	 * complete last, if this is a stack request the process (and thus
-	 * the rq pointer) could be invalid right after this complete()
-	 */
-	complete(waiting);
-}
-EXPORT_SYMBOL(blk_end_sync_rq);
-
-/**
- * blk_congestion_wait - wait for a queue to become uncongested
- * @rw: READ or WRITE
- * @timeout: timeout in jiffies
- *
- * Waits for up to @timeout jiffies for a queue (any queue) to exit congestion.
- * If no queues are congested then just wait for the next request to be
- * returned.
- */
-long blk_congestion_wait(int rw, long timeout)
-{
-	long ret;
-	DEFINE_WAIT(wait);
-	wait_queue_head_t *wqh = &congestion_wqh[rw];
-
-	prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
-	ret = io_schedule_timeout(timeout);
-	finish_wait(wqh, &wait);
-	return ret;
-}
-
-EXPORT_SYMBOL(blk_congestion_wait);
-
-/*
- * Has to be called with the request spinlock acquired
- */
-static int attempt_merge(request_queue_t *q, struct request *req,
-			  struct request *next)
-{
-	if (!rq_mergeable(req) || !rq_mergeable(next))
-		return 0;
-
-	/*
-	 * not contigious
-	 */
-	if (req->sector + req->nr_sectors != next->sector)
-		return 0;
-
-	if (rq_data_dir(req) != rq_data_dir(next)
-	    || req->rq_disk != next->rq_disk
-	    || next->waiting || next->special)
-		return 0;
-
-	/*
-	 * If we are allowed to merge, then append bio list
-	 * from next to rq and release next. merge_requests_fn
-	 * will have updated segment counts, update sector
-	 * counts here.
-	 */
-	if (!q->merge_requests_fn(q, req, next))
-		return 0;
-
-	/*
-	 * At this point we have either done a back merge
-	 * or front merge. We need the smaller start_time of
-	 * the merged requests to be the current request
-	 * for accounting purposes.
-	 */
-	if (time_after(req->start_time, next->start_time))
-		req->start_time = next->start_time;
-
-	req->biotail->bi_next = next->bio;
-	req->biotail = next->biotail;
-
-	req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors;
-
-	elv_merge_requests(q, req, next);
-
-	if (req->rq_disk) {
-		disk_round_stats(req->rq_disk);
-		req->rq_disk->in_flight--;
-	}
-
-	req->ioprio = ioprio_best(req->ioprio, next->ioprio);
-
-	__blk_put_request(q, next);
-	return 1;
-}
-
-static inline int attempt_back_merge(request_queue_t *q, struct request *rq)
-{
-	struct request *next = elv_latter_request(q, rq);
-
-	if (next)
-		return attempt_merge(q, rq, next);
-
-	return 0;
-}
-
-static inline int attempt_front_merge(request_queue_t *q, struct request *rq)
-{
-	struct request *prev = elv_former_request(q, rq);
-
-	if (prev)
-		return attempt_merge(q, prev, rq);
-
-	return 0;
-}
-
-/**
- * blk_attempt_remerge  - attempt to remerge active head with next request
- * @q:    The &request_queue_t belonging to the device
- * @rq:   The head request (usually)
- *
- * Description:
- *    For head-active devices, the queue can easily be unplugged so quickly
- *    that proper merging is not done on the front request. This may hurt
- *    performance greatly for some devices. The block layer cannot safely
- *    do merging on that first request for these queues, but the driver can
- *    call this function and make it happen any way. Only the driver knows
- *    when it is safe to do so.
- **/
-void blk_attempt_remerge(request_queue_t *q, struct request *rq)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(q->queue_lock, flags);
-	attempt_back_merge(q, rq);
-	spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-EXPORT_SYMBOL(blk_attempt_remerge);
-
-static int __make_request(request_queue_t *q, struct bio *bio)
-{
-	struct request *req;
-	int el_ret, rw, nr_sectors, cur_nr_sectors, barrier, err, sync;
-	unsigned short prio;
-	sector_t sector;
-
-	sector = bio->bi_sector;
-	nr_sectors = bio_sectors(bio);
-	cur_nr_sectors = bio_cur_sectors(bio);
-	prio = bio_prio(bio);
-
-	rw = bio_data_dir(bio);
-	sync = bio_sync(bio);
-
-	/*
-	 * low level driver can indicate that it wants pages above a
-	 * certain limit bounced to low memory (ie for highmem, or even
-	 * ISA dma in theory)
-	 */
-	blk_queue_bounce(q, &bio);
-
-	spin_lock_prefetch(q->queue_lock);
-
-	barrier = bio_barrier(bio);
-	if (unlikely(barrier) && (q->ordered == QUEUE_ORDERED_NONE)) {
-		err = -EOPNOTSUPP;
-		goto end_io;
-	}
-
-	spin_lock_irq(q->queue_lock);
-
-	if (unlikely(barrier) || elv_queue_empty(q))
-		goto get_rq;
-
-	el_ret = elv_merge(q, &req, bio);
-	switch (el_ret) {
-		case ELEVATOR_BACK_MERGE:
-			BUG_ON(!rq_mergeable(req));
-
-			if (!q->back_merge_fn(q, req, bio))
-				break;
-
-			req->biotail->bi_next = bio;
-			req->biotail = bio;
-			req->nr_sectors = req->hard_nr_sectors += nr_sectors;
-			req->ioprio = ioprio_best(req->ioprio, prio);
-			drive_stat_acct(req, nr_sectors, 0);
-			if (!attempt_back_merge(q, req))
-				elv_merged_request(q, req);
-			goto out;
-
-		case ELEVATOR_FRONT_MERGE:
-			BUG_ON(!rq_mergeable(req));
-
-			if (!q->front_merge_fn(q, req, bio))
-				break;
-
-			bio->bi_next = req->bio;
-			req->bio = bio;
-
-			/*
-			 * may not be valid. if the low level driver said
-			 * it didn't need a bounce buffer then it better
-			 * not touch req->buffer either...
-			 */
-			req->buffer = bio_data(bio);
-			req->current_nr_sectors = cur_nr_sectors;
-			req->hard_cur_sectors = cur_nr_sectors;
-			req->sector = req->hard_sector = sector;
-			req->nr_sectors = req->hard_nr_sectors += nr_sectors;
-			req->ioprio = ioprio_best(req->ioprio, prio);
-			drive_stat_acct(req, nr_sectors, 0);
-			if (!attempt_front_merge(q, req))
-				elv_merged_request(q, req);
-			goto out;
-
-		/* ELV_NO_MERGE: elevator says don't/can't merge. */
-		default:
-			;
-	}
-
-get_rq:
-	/*
-	 * Grab a free request. This is might sleep but can not fail.
-	 * Returns with the queue unlocked.
-	 */
-	req = get_request_wait(q, rw, bio);
-
-	/*
-	 * After dropping the lock and possibly sleeping here, our request
-	 * may now be mergeable after it had proven unmergeable (above).
-	 * We don't worry about that case for efficiency. It won't happen
-	 * often, and the elevators are able to handle it.
-	 */
-
-	req->flags |= REQ_CMD;
-
-	/*
-	 * inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST)
-	 */
-	if (bio_rw_ahead(bio) || bio_failfast(bio))
-		req->flags |= REQ_FAILFAST;
-
-	/*
-	 * REQ_BARRIER implies no merging, but lets make it explicit
-	 */
-	if (unlikely(barrier))
-		req->flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
-
-	req->errors = 0;
-	req->hard_sector = req->sector = sector;
-	req->hard_nr_sectors = req->nr_sectors = nr_sectors;
-	req->current_nr_sectors = req->hard_cur_sectors = cur_nr_sectors;
-	req->nr_phys_segments = bio_phys_segments(q, bio);
-	req->nr_hw_segments = bio_hw_segments(q, bio);
-	req->buffer = bio_data(bio);	/* see ->buffer comment above */
-	req->waiting = NULL;
-	req->bio = req->biotail = bio;
-	req->ioprio = prio;
-	req->rq_disk = bio->bi_bdev->bd_disk;
-	req->start_time = jiffies;
-
-	spin_lock_irq(q->queue_lock);
-	if (elv_queue_empty(q))
-		blk_plug_device(q);
-	add_request(q, req);
-out:
-	if (sync)
-		__generic_unplug_device(q);
-
-	spin_unlock_irq(q->queue_lock);
-	return 0;
-
-end_io:
-	bio_endio(bio, nr_sectors << 9, err);
-	return 0;
-}
-
-/*
- * If bio->bi_dev is a partition, remap the location
- */
-static inline void blk_partition_remap(struct bio *bio)
-{
-	struct block_device *bdev = bio->bi_bdev;
-
-	if (bdev != bdev->bd_contains) {
-		struct hd_struct *p = bdev->bd_part;
-		const int rw = bio_data_dir(bio);
-
-		p->sectors[rw] += bio_sectors(bio);
-		p->ios[rw]++;
-
-		bio->bi_sector += p->start_sect;
-		bio->bi_bdev = bdev->bd_contains;
-	}
-}
-
-static void handle_bad_sector(struct bio *bio)
-{
-	char b[BDEVNAME_SIZE];
-
-	printk(KERN_INFO "attempt to access beyond end of device\n");
-	printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n",
-			bdevname(bio->bi_bdev, b),
-			bio->bi_rw,
-			(unsigned long long)bio->bi_sector + bio_sectors(bio),
-			(long long)(bio->bi_bdev->bd_inode->i_size >> 9));
-
-	set_bit(BIO_EOF, &bio->bi_flags);
-}
-
-/**
- * generic_make_request: hand a buffer to its device driver for I/O
- * @bio:  The bio describing the location in memory and on the device.
- *
- * generic_make_request() is used to make I/O requests of block
- * devices. It is passed a &struct bio, which describes the I/O that needs
- * to be done.
- *
- * generic_make_request() does not return any status.  The
- * success/failure status of the request, along with notification of
- * completion, is delivered asynchronously through the bio->bi_end_io
- * function described (one day) else where.
- *
- * The caller of generic_make_request must make sure that bi_io_vec
- * are set to describe the memory buffer, and that bi_dev and bi_sector are
- * set to describe the device address, and the
- * bi_end_io and optionally bi_private are set to describe how
- * completion notification should be signaled.
- *
- * generic_make_request and the drivers it calls may use bi_next if this
- * bio happens to be merged with someone else, and may change bi_dev and
- * bi_sector for remaps as it sees fit.  So the values of these fields
- * should NOT be depended on after the call to generic_make_request.
- */
-void generic_make_request(struct bio *bio)
-{
-	request_queue_t *q;
-	sector_t maxsector;
-	int ret, nr_sectors = bio_sectors(bio);
-
-	might_sleep();
-	/* Test device or partition size, when known. */
-	maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
-	if (maxsector) {
-		sector_t sector = bio->bi_sector;
-
-		if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
-			/*
-			 * This may well happen - the kernel calls bread()
-			 * without checking the size of the device, e.g., when
-			 * mounting a device.
-			 */
-			handle_bad_sector(bio);
-			goto end_io;
-		}
-	}
-
-	/*
-	 * Resolve the mapping until finished. (drivers are
-	 * still free to implement/resolve their own stacking
-	 * by explicitly returning 0)
-	 *
-	 * NOTE: we don't repeat the blk_size check for each new device.
-	 * Stacking drivers are expected to know what they are doing.
-	 */
-	do {
-		char b[BDEVNAME_SIZE];
-
-		q = bdev_get_queue(bio->bi_bdev);
-		if (!q) {
-			printk(KERN_ERR
-			       "generic_make_request: Trying to access "
-				"nonexistent block-device %s (%Lu)\n",
-				bdevname(bio->bi_bdev, b),
-				(long long) bio->bi_sector);
-end_io:
-			bio_endio(bio, bio->bi_size, -EIO);
-			break;
-		}
-
-		if (unlikely(bio_sectors(bio) > q->max_hw_sectors)) {
-			printk("bio too big device %s (%u > %u)\n", 
-				bdevname(bio->bi_bdev, b),
-				bio_sectors(bio),
-				q->max_hw_sectors);
-			goto end_io;
-		}
-
-		if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
-			goto end_io;
-
-		/*
-		 * If this device has partitions, remap block n
-		 * of partition p to block n+start(p) of the disk.
-		 */
-		blk_partition_remap(bio);
-
-		ret = q->make_request_fn(q, bio);
-	} while (ret);
-}
-
-EXPORT_SYMBOL(generic_make_request);
-
-/**
- * submit_bio: submit a bio to the block device layer for I/O
- * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
- * @bio: The &struct bio which describes the I/O
- *
- * submit_bio() is very similar in purpose to generic_make_request(), and
- * uses that function to do most of the work. Both are fairly rough
- * interfaces, @bio must be presetup and ready for I/O.
- *
- */
-void submit_bio(int rw, struct bio *bio)
-{
-	int count = bio_sectors(bio);
-
-	BIO_BUG_ON(!bio->bi_size);
-	BIO_BUG_ON(!bio->bi_io_vec);
-	bio->bi_rw |= rw;
-	if (rw & WRITE)
-		mod_page_state(pgpgout, count);
-	else
-		mod_page_state(pgpgin, count);
-
-	if (unlikely(block_dump)) {
-		char b[BDEVNAME_SIZE];
-		printk(KERN_DEBUG "%s(%d): %s block %Lu on %s\n",
-			current->comm, current->pid,
-			(rw & WRITE) ? "WRITE" : "READ",
-			(unsigned long long)bio->bi_sector,
-			bdevname(bio->bi_bdev,b));
-	}
-
-	generic_make_request(bio);
-}
-
-EXPORT_SYMBOL(submit_bio);
-
-static void blk_recalc_rq_segments(struct request *rq)
-{
-	struct bio *bio, *prevbio = NULL;
-	int nr_phys_segs, nr_hw_segs;
-	unsigned int phys_size, hw_size;
-	request_queue_t *q = rq->q;
-
-	if (!rq->bio)
-		return;
-
-	phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
-	rq_for_each_bio(bio, rq) {
-		/* Force bio hw/phys segs to be recalculated. */
-		bio->bi_flags &= ~(1 << BIO_SEG_VALID);
-
-		nr_phys_segs += bio_phys_segments(q, bio);
-		nr_hw_segs += bio_hw_segments(q, bio);
-		if (prevbio) {
-			int pseg = phys_size + prevbio->bi_size + bio->bi_size;
-			int hseg = hw_size + prevbio->bi_size + bio->bi_size;
-
-			if (blk_phys_contig_segment(q, prevbio, bio) &&
-			    pseg <= q->max_segment_size) {
-				nr_phys_segs--;
-				phys_size += prevbio->bi_size + bio->bi_size;
-			} else
-				phys_size = 0;
-
-			if (blk_hw_contig_segment(q, prevbio, bio) &&
-			    hseg <= q->max_segment_size) {
-				nr_hw_segs--;
-				hw_size += prevbio->bi_size + bio->bi_size;
-			} else
-				hw_size = 0;
-		}
-		prevbio = bio;
-	}
-
-	rq->nr_phys_segments = nr_phys_segs;
-	rq->nr_hw_segments = nr_hw_segs;
-}
-
-static void blk_recalc_rq_sectors(struct request *rq, int nsect)
-{
-	if (blk_fs_request(rq)) {
-		rq->hard_sector += nsect;
-		rq->hard_nr_sectors -= nsect;
-
-		/*
-		 * Move the I/O submission pointers ahead if required.
-		 */
-		if ((rq->nr_sectors >= rq->hard_nr_sectors) &&
-		    (rq->sector <= rq->hard_sector)) {
-			rq->sector = rq->hard_sector;
-			rq->nr_sectors = rq->hard_nr_sectors;
-			rq->hard_cur_sectors = bio_cur_sectors(rq->bio);
-			rq->current_nr_sectors = rq->hard_cur_sectors;
-			rq->buffer = bio_data(rq->bio);
-		}
-
-		/*
-		 * if total number of sectors is less than the first segment
-		 * size, something has gone terribly wrong
-		 */
-		if (rq->nr_sectors < rq->current_nr_sectors) {
-			printk("blk: request botched\n");
-			rq->nr_sectors = rq->current_nr_sectors;
-		}
-	}
-}
-
-static int __end_that_request_first(struct request *req, int uptodate,
-				    int nr_bytes)
-{
-	int total_bytes, bio_nbytes, error, next_idx = 0;
-	struct bio *bio;
-
-	/*
-	 * extend uptodate bool to allow < 0 value to be direct io error
-	 */
-	error = 0;
-	if (end_io_error(uptodate))
-		error = !uptodate ? -EIO : uptodate;
-
-	/*
-	 * for a REQ_BLOCK_PC request, we want to carry any eventual
-	 * sense key with us all the way through
-	 */
-	if (!blk_pc_request(req))
-		req->errors = 0;
-
-	if (!uptodate) {
-		if (blk_fs_request(req) && !(req->flags & REQ_QUIET))
-			printk("end_request: I/O error, dev %s, sector %llu\n",
-				req->rq_disk ? req->rq_disk->disk_name : "?",
-				(unsigned long long)req->sector);
-	}
-
-	if (blk_fs_request(req) && req->rq_disk) {
-		const int rw = rq_data_dir(req);
-
-		__disk_stat_add(req->rq_disk, sectors[rw], nr_bytes >> 9);
-	}
-
-	total_bytes = bio_nbytes = 0;
-	while ((bio = req->bio) != NULL) {
-		int nbytes;
-
-		if (nr_bytes >= bio->bi_size) {
-			req->bio = bio->bi_next;
-			nbytes = bio->bi_size;
-			bio_endio(bio, nbytes, error);
-			next_idx = 0;
-			bio_nbytes = 0;
-		} else {
-			int idx = bio->bi_idx + next_idx;
-
-			if (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
-				blk_dump_rq_flags(req, "__end_that");
-				printk("%s: bio idx %d >= vcnt %d\n",
-						__FUNCTION__,
-						bio->bi_idx, bio->bi_vcnt);
-				break;
-			}
-
-			nbytes = bio_iovec_idx(bio, idx)->bv_len;
-			BIO_BUG_ON(nbytes > bio->bi_size);
-
-			/*
-			 * not a complete bvec done
-			 */
-			if (unlikely(nbytes > nr_bytes)) {
-				bio_nbytes += nr_bytes;
-				total_bytes += nr_bytes;
-				break;
-			}
-
-			/*
-			 * advance to the next vector
-			 */
-			next_idx++;
-			bio_nbytes += nbytes;
-		}
-
-		total_bytes += nbytes;
-		nr_bytes -= nbytes;
-
-		if ((bio = req->bio)) {
-			/*
-			 * end more in this run, or just return 'not-done'
-			 */
-			if (unlikely(nr_bytes <= 0))
-				break;
-		}
-	}
-
-	/*
-	 * completely done
-	 */
-	if (!req->bio)
-		return 0;
-
-	/*
-	 * if the request wasn't completed, update state
-	 */
-	if (bio_nbytes) {
-		bio_endio(bio, bio_nbytes, error);
-		bio->bi_idx += next_idx;
-		bio_iovec(bio)->bv_offset += nr_bytes;
-		bio_iovec(bio)->bv_len -= nr_bytes;
-	}
-
-	blk_recalc_rq_sectors(req, total_bytes >> 9);
-	blk_recalc_rq_segments(req);
-	return 1;
-}
-
-/**
- * end_that_request_first - end I/O on a request
- * @req:      the request being processed
- * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error
- * @nr_sectors: number of sectors to end I/O on
- *
- * Description:
- *     Ends I/O on a number of sectors attached to @req, and sets it up
- *     for the next range of segments (if any) in the cluster.
- *
- * Return:
- *     0 - we are done with this request, call end_that_request_last()
- *     1 - still buffers pending for this request
- **/
-int end_that_request_first(struct request *req, int uptodate, int nr_sectors)
-{
-	return __end_that_request_first(req, uptodate, nr_sectors << 9);
-}
-
-EXPORT_SYMBOL(end_that_request_first);
-
-/**
- * end_that_request_chunk - end I/O on a request
- * @req:      the request being processed
- * @uptodate: 1 for success, 0 for I/O error, < 0 for specific error
- * @nr_bytes: number of bytes to complete
- *
- * Description:
- *     Ends I/O on a number of bytes attached to @req, and sets it up
- *     for the next range of segments (if any). Like end_that_request_first(),
- *     but deals with bytes instead of sectors.
- *
- * Return:
- *     0 - we are done with this request, call end_that_request_last()
- *     1 - still buffers pending for this request
- **/
-int end_that_request_chunk(struct request *req, int uptodate, int nr_bytes)
-{
-	return __end_that_request_first(req, uptodate, nr_bytes);
-}
-
-EXPORT_SYMBOL(end_that_request_chunk);
-
-/*
- * queue lock must be held
- */
-void end_that_request_last(struct request *req)
-{
-	struct gendisk *disk = req->rq_disk;
-
-	if (unlikely(laptop_mode) && blk_fs_request(req))
-		laptop_io_completion();
-
-	if (disk && blk_fs_request(req)) {
-		unsigned long duration = jiffies - req->start_time;
-		const int rw = rq_data_dir(req);
-
-		__disk_stat_inc(disk, ios[rw]);
-		__disk_stat_add(disk, ticks[rw], duration);
-		disk_round_stats(disk);
-		disk->in_flight--;
-	}
-	if (req->end_io)
-		req->end_io(req);
-	else
-		__blk_put_request(req->q, req);
-}
-
-EXPORT_SYMBOL(end_that_request_last);
-
-void end_request(struct request *req, int uptodate)
-{
-	if (!end_that_request_first(req, uptodate, req->hard_cur_sectors)) {
-		add_disk_randomness(req->rq_disk);
-		blkdev_dequeue_request(req);
-		end_that_request_last(req);
-	}
-}
-
-EXPORT_SYMBOL(end_request);
-
-void blk_rq_bio_prep(request_queue_t *q, struct request *rq, struct bio *bio)
-{
-	/* first three bits are identical in rq->flags and bio->bi_rw */
-	rq->flags |= (bio->bi_rw & 7);
-
-	rq->nr_phys_segments = bio_phys_segments(q, bio);
-	rq->nr_hw_segments = bio_hw_segments(q, bio);
-	rq->current_nr_sectors = bio_cur_sectors(bio);
-	rq->hard_cur_sectors = rq->current_nr_sectors;
-	rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(bio);
-	rq->buffer = bio_data(bio);
-
-	rq->bio = rq->biotail = bio;
-}
-
-EXPORT_SYMBOL(blk_rq_bio_prep);
-
-int kblockd_schedule_work(struct work_struct *work)
-{
-	return queue_work(kblockd_workqueue, work);
-}
-
-EXPORT_SYMBOL(kblockd_schedule_work);
-
-void kblockd_flush(void)
-{
-	flush_workqueue(kblockd_workqueue);
-}
-EXPORT_SYMBOL(kblockd_flush);
-
-int __init blk_dev_init(void)
-{
-	kblockd_workqueue = create_workqueue("kblockd");
-	if (!kblockd_workqueue)
-		panic("Failed to create kblockd\n");
-
-	request_cachep = kmem_cache_create("blkdev_requests",
-			sizeof(struct request), 0, SLAB_PANIC, NULL, NULL);
-
-	requestq_cachep = kmem_cache_create("blkdev_queue",
-			sizeof(request_queue_t), 0, SLAB_PANIC, NULL, NULL);
-
-	iocontext_cachep = kmem_cache_create("blkdev_ioc",
-			sizeof(struct io_context), 0, SLAB_PANIC, NULL, NULL);
-
-	blk_max_low_pfn = max_low_pfn;
-	blk_max_pfn = max_pfn;
-
-	return 0;
-}
-
-/*
- * IO Context helper functions
- */
-void put_io_context(struct io_context *ioc)
-{
-	if (ioc == NULL)
-		return;
-
-	BUG_ON(atomic_read(&ioc->refcount) == 0);
-
-	if (atomic_dec_and_test(&ioc->refcount)) {
-		if (ioc->aic && ioc->aic->dtor)
-			ioc->aic->dtor(ioc->aic);
-		if (ioc->cic && ioc->cic->dtor)
-			ioc->cic->dtor(ioc->cic);
-
-		kmem_cache_free(iocontext_cachep, ioc);
-	}
-}
-EXPORT_SYMBOL(put_io_context);
-
-/* Called by the exitting task */
-void exit_io_context(void)
-{
-	unsigned long flags;
-	struct io_context *ioc;
-
-	local_irq_save(flags);
-	task_lock(current);
-	ioc = current->io_context;
-	current->io_context = NULL;
-	ioc->task = NULL;
-	task_unlock(current);
-	local_irq_restore(flags);
-
-	if (ioc->aic && ioc->aic->exit)
-		ioc->aic->exit(ioc->aic);
-	if (ioc->cic && ioc->cic->exit)
-		ioc->cic->exit(ioc->cic);
-
-	put_io_context(ioc);
-}
-
-/*
- * If the current task has no IO context then create one and initialise it.
- * Otherwise, return its existing IO context.
- *
- * This returned IO context doesn't have a specifically elevated refcount,
- * but since the current task itself holds a reference, the context can be
- * used in general code, so long as it stays within `current` context.
- */
-struct io_context *current_io_context(gfp_t gfp_flags)
-{
-	struct task_struct *tsk = current;
-	struct io_context *ret;
-
-	ret = tsk->io_context;
-	if (likely(ret))
-		return ret;
-
-	ret = kmem_cache_alloc(iocontext_cachep, gfp_flags);
-	if (ret) {
-		atomic_set(&ret->refcount, 1);
-		ret->task = current;
-		ret->set_ioprio = NULL;
-		ret->last_waited = jiffies; /* doesn't matter... */
-		ret->nr_batch_requests = 0; /* because this is 0 */
-		ret->aic = NULL;
-		ret->cic = NULL;
-		tsk->io_context = ret;
-	}
-
-	return ret;
-}
-EXPORT_SYMBOL(current_io_context);
-
-/*
- * If the current task has no IO context then create one and initialise it.
- * If it does have a context, take a ref on it.
- *
- * This is always called in the context of the task which submitted the I/O.
- */
-struct io_context *get_io_context(gfp_t gfp_flags)
-{
-	struct io_context *ret;
-	ret = current_io_context(gfp_flags);
-	if (likely(ret))
-		atomic_inc(&ret->refcount);
-	return ret;
-}
-EXPORT_SYMBOL(get_io_context);
-
-void copy_io_context(struct io_context **pdst, struct io_context **psrc)
-{
-	struct io_context *src = *psrc;
-	struct io_context *dst = *pdst;
-
-	if (src) {
-		BUG_ON(atomic_read(&src->refcount) == 0);
-		atomic_inc(&src->refcount);
-		put_io_context(dst);
-		*pdst = src;
-	}
-}
-EXPORT_SYMBOL(copy_io_context);
-
-void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
-{
-	struct io_context *temp;
-	temp = *ioc1;
-	*ioc1 = *ioc2;
-	*ioc2 = temp;
-}
-EXPORT_SYMBOL(swap_io_context);
-
-/*
- * sysfs parts below
- */
-struct queue_sysfs_entry {
-	struct attribute attr;
-	ssize_t (*show)(struct request_queue *, char *);
-	ssize_t (*store)(struct request_queue *, const char *, size_t);
-};
-
-static ssize_t
-queue_var_show(unsigned int var, char *page)
-{
-	return sprintf(page, "%d\n", var);
-}
-
-static ssize_t
-queue_var_store(unsigned long *var, const char *page, size_t count)
-{
-	char *p = (char *) page;
-
-	*var = simple_strtoul(p, &p, 10);
-	return count;
-}
-
-static ssize_t queue_requests_show(struct request_queue *q, char *page)
-{
-	return queue_var_show(q->nr_requests, (page));
-}
-
-static ssize_t
-queue_requests_store(struct request_queue *q, const char *page, size_t count)
-{
-	struct request_list *rl = &q->rq;
-
-	int ret = queue_var_store(&q->nr_requests, page, count);
-	if (q->nr_requests < BLKDEV_MIN_RQ)
-		q->nr_requests = BLKDEV_MIN_RQ;
-	blk_queue_congestion_threshold(q);
-
-	if (rl->count[READ] >= queue_congestion_on_threshold(q))
-		set_queue_congested(q, READ);
-	else if (rl->count[READ] < queue_congestion_off_threshold(q))
-		clear_queue_congested(q, READ);
-
-	if (rl->count[WRITE] >= queue_congestion_on_threshold(q))
-		set_queue_congested(q, WRITE);
-	else if (rl->count[WRITE] < queue_congestion_off_threshold(q))
-		clear_queue_congested(q, WRITE);
-
-	if (rl->count[READ] >= q->nr_requests) {
-		blk_set_queue_full(q, READ);
-	} else if (rl->count[READ]+1 <= q->nr_requests) {
-		blk_clear_queue_full(q, READ);
-		wake_up(&rl->wait[READ]);
-	}
-
-	if (rl->count[WRITE] >= q->nr_requests) {
-		blk_set_queue_full(q, WRITE);
-	} else if (rl->count[WRITE]+1 <= q->nr_requests) {
-		blk_clear_queue_full(q, WRITE);
-		wake_up(&rl->wait[WRITE]);
-	}
-	return ret;
-}
-
-static ssize_t queue_ra_show(struct request_queue *q, char *page)
-{
-	int ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
-
-	return queue_var_show(ra_kb, (page));
-}
-
-static ssize_t
-queue_ra_store(struct request_queue *q, const char *page, size_t count)
-{
-	unsigned long ra_kb;
-	ssize_t ret = queue_var_store(&ra_kb, page, count);
-
-	spin_lock_irq(q->queue_lock);
-	if (ra_kb > (q->max_sectors >> 1))
-		ra_kb = (q->max_sectors >> 1);
-
-	q->backing_dev_info.ra_pages = ra_kb >> (PAGE_CACHE_SHIFT - 10);
-	spin_unlock_irq(q->queue_lock);
-
-	return ret;
-}
-
-static ssize_t queue_max_sectors_show(struct request_queue *q, char *page)
-{
-	int max_sectors_kb = q->max_sectors >> 1;
-
-	return queue_var_show(max_sectors_kb, (page));
-}
-
-static ssize_t
-queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
-{
-	unsigned long max_sectors_kb,
-			max_hw_sectors_kb = q->max_hw_sectors >> 1,
-			page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
-	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
-	int ra_kb;
-
-	if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
-		return -EINVAL;
-	/*
-	 * Take the queue lock to update the readahead and max_sectors
-	 * values synchronously:
-	 */
-	spin_lock_irq(q->queue_lock);
-	/*
-	 * Trim readahead window as well, if necessary:
-	 */
-	ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
-	if (ra_kb > max_sectors_kb)
-		q->backing_dev_info.ra_pages =
-				max_sectors_kb >> (PAGE_CACHE_SHIFT - 10);
-
-	q->max_sectors = max_sectors_kb << 1;
-	spin_unlock_irq(q->queue_lock);
-
-	return ret;
-}
-
-static ssize_t queue_max_hw_sectors_show(struct request_queue *q, char *page)
-{
-	int max_hw_sectors_kb = q->max_hw_sectors >> 1;
-
-	return queue_var_show(max_hw_sectors_kb, (page));
-}
-
-
-static struct queue_sysfs_entry queue_requests_entry = {
-	.attr = {.name = "nr_requests", .mode = S_IRUGO | S_IWUSR },
-	.show = queue_requests_show,
-	.store = queue_requests_store,
-};
-
-static struct queue_sysfs_entry queue_ra_entry = {
-	.attr = {.name = "read_ahead_kb", .mode = S_IRUGO | S_IWUSR },
-	.show = queue_ra_show,
-	.store = queue_ra_store,
-};
-
-static struct queue_sysfs_entry queue_max_sectors_entry = {
-	.attr = {.name = "max_sectors_kb", .mode = S_IRUGO | S_IWUSR },
-	.show = queue_max_sectors_show,
-	.store = queue_max_sectors_store,
-};
-
-static struct queue_sysfs_entry queue_max_hw_sectors_entry = {
-	.attr = {.name = "max_hw_sectors_kb", .mode = S_IRUGO },
-	.show = queue_max_hw_sectors_show,
-};
-
-static struct queue_sysfs_entry queue_iosched_entry = {
-	.attr = {.name = "scheduler", .mode = S_IRUGO | S_IWUSR },
-	.show = elv_iosched_show,
-	.store = elv_iosched_store,
-};
-
-static struct attribute *default_attrs[] = {
-	&queue_requests_entry.attr,
-	&queue_ra_entry.attr,
-	&queue_max_hw_sectors_entry.attr,
-	&queue_max_sectors_entry.attr,
-	&queue_iosched_entry.attr,
-	NULL,
-};
-
-#define to_queue(atr) container_of((atr), struct queue_sysfs_entry, attr)
-
-static ssize_t
-queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page)
-{
-	struct queue_sysfs_entry *entry = to_queue(attr);
-	struct request_queue *q;
-
-	q = container_of(kobj, struct request_queue, kobj);
-	if (!entry->show)
-		return -EIO;
-
-	return entry->show(q, page);
-}
-
-static ssize_t
-queue_attr_store(struct kobject *kobj, struct attribute *attr,
-		    const char *page, size_t length)
-{
-	struct queue_sysfs_entry *entry = to_queue(attr);
-	struct request_queue *q;
-
-	q = container_of(kobj, struct request_queue, kobj);
-	if (!entry->store)
-		return -EIO;
-
-	return entry->store(q, page, length);
-}
-
-static struct sysfs_ops queue_sysfs_ops = {
-	.show	= queue_attr_show,
-	.store	= queue_attr_store,
-};
-
-static struct kobj_type queue_ktype = {
-	.sysfs_ops	= &queue_sysfs_ops,
-	.default_attrs	= default_attrs,
-};
-
-int blk_register_queue(struct gendisk *disk)
-{
-	int ret;
-
-	request_queue_t *q = disk->queue;
-
-	if (!q || !q->request_fn)
-		return -ENXIO;
-
-	q->kobj.parent = kobject_get(&disk->kobj);
-	if (!q->kobj.parent)
-		return -EBUSY;
-
-	snprintf(q->kobj.name, KOBJ_NAME_LEN, "%s", "queue");
-	q->kobj.ktype = &queue_ktype;
-
-	ret = kobject_register(&q->kobj);
-	if (ret < 0)
-		return ret;
-
-	ret = elv_register_queue(q);
-	if (ret) {
-		kobject_unregister(&q->kobj);
-		return ret;
-	}
-
-	return 0;
-}
-
-void blk_unregister_queue(struct gendisk *disk)
-{
-	request_queue_t *q = disk->queue;
-
-	if (q && q->request_fn) {
-		elv_unregister_queue(q);
-
-		kobject_unregister(&q->kobj);
-		kobject_put(&disk->kobj);
-	}
-}
diff --git a/drivers/block/noop-iosched.c b/drivers/block/noop-iosched.c
deleted file mode 100644
index e54f006e7e60..000000000000
--- a/drivers/block/noop-iosched.c
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * elevator noop
- */
-#include <linux/blkdev.h>
-#include <linux/elevator.h>
-#include <linux/bio.h>
-#include <linux/module.h>
-#include <linux/init.h>
-
-static void elevator_noop_add_request(request_queue_t *q, struct request *rq)
-{
-	rq->flags |= REQ_NOMERGE;
-	elv_dispatch_add_tail(q, rq);
-}
-
-static int elevator_noop_dispatch(request_queue_t *q, int force)
-{
-	return 0;
-}
-
-static struct elevator_type elevator_noop = {
-	.ops = {
-		.elevator_dispatch_fn		= elevator_noop_dispatch,
-		.elevator_add_req_fn		= elevator_noop_add_request,
-	},
-	.elevator_name = "noop",
-	.elevator_owner = THIS_MODULE,
-};
-
-static int __init noop_init(void)
-{
-	return elv_register(&elevator_noop);
-}
-
-static void __exit noop_exit(void)
-{
-	elv_unregister(&elevator_noop);
-}
-
-module_init(noop_init);
-module_exit(noop_exit);
-
-
-MODULE_AUTHOR("Jens Axboe");
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("No-op IO scheduler");
diff --git a/drivers/block/scsi_ioctl.c b/drivers/block/scsi_ioctl.c
deleted file mode 100644
index 382dea7b224c..000000000000
--- a/drivers/block/scsi_ioctl.c
+++ /dev/null
@@ -1,589 +0,0 @@
-/*
- * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- *
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public Licens
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
- *
- */
-#include <linux/kernel.h>
-#include <linux/errno.h>
-#include <linux/string.h>
-#include <linux/module.h>
-#include <linux/blkdev.h>
-#include <linux/completion.h>
-#include <linux/cdrom.h>
-#include <linux/slab.h>
-#include <linux/times.h>
-#include <asm/uaccess.h>
-
-#include <scsi/scsi.h>
-#include <scsi/scsi_ioctl.h>
-#include <scsi/scsi_cmnd.h>
-
-/* Command group 3 is reserved and should never be used.  */
-const unsigned char scsi_command_size[8] =
-{
-	6, 10, 10, 12,
-	16, 12, 10, 10
-};
-
-EXPORT_SYMBOL(scsi_command_size);
-
-#define BLK_DEFAULT_TIMEOUT	(60 * HZ)
-
-#include <scsi/sg.h>
-
-static int sg_get_version(int __user *p)
-{
-	static int sg_version_num = 30527;
-	return put_user(sg_version_num, p);
-}
-
-static int scsi_get_idlun(request_queue_t *q, int __user *p)
-{
-	return put_user(0, p);
-}
-
-static int scsi_get_bus(request_queue_t *q, int __user *p)
-{
-	return put_user(0, p);
-}
-
-static int sg_get_timeout(request_queue_t *q)
-{
-	return q->sg_timeout / (HZ / USER_HZ);
-}
-
-static int sg_set_timeout(request_queue_t *q, int __user *p)
-{
-	int timeout, err = get_user(timeout, p);
-
-	if (!err)
-		q->sg_timeout = timeout * (HZ / USER_HZ);
-
-	return err;
-}
-
-static int sg_get_reserved_size(request_queue_t *q, int __user *p)
-{
-	return put_user(q->sg_reserved_size, p);
-}
-
-static int sg_set_reserved_size(request_queue_t *q, int __user *p)
-{
-	int size, err = get_user(size, p);
-
-	if (err)
-		return err;
-
-	if (size < 0)
-		return -EINVAL;
-	if (size > (q->max_sectors << 9))
-		size = q->max_sectors << 9;
-
-	q->sg_reserved_size = size;
-	return 0;
-}
-
-/*
- * will always return that we are ATAPI even for a real SCSI drive, I'm not
- * so sure this is worth doing anything about (why would you care??)
- */
-static int sg_emulated_host(request_queue_t *q, int __user *p)
-{
-	return put_user(1, p);
-}
-
-#define CMD_READ_SAFE	0x01
-#define CMD_WRITE_SAFE	0x02
-#define CMD_WARNED	0x04
-#define safe_for_read(cmd)	[cmd] = CMD_READ_SAFE
-#define safe_for_write(cmd)	[cmd] = CMD_WRITE_SAFE
-
-static int verify_command(struct file *file, unsigned char *cmd)
-{
-	static unsigned char cmd_type[256] = {
-
-		/* Basic read-only commands */
-		safe_for_read(TEST_UNIT_READY),
-		safe_for_read(REQUEST_SENSE),
-		safe_for_read(READ_6),
-		safe_for_read(READ_10),
-		safe_for_read(READ_12),
-		safe_for_read(READ_16),
-		safe_for_read(READ_BUFFER),
-		safe_for_read(READ_DEFECT_DATA),
-		safe_for_read(READ_LONG),
-		safe_for_read(INQUIRY),
-		safe_for_read(MODE_SENSE),
-		safe_for_read(MODE_SENSE_10),
-		safe_for_read(LOG_SENSE),
-		safe_for_read(START_STOP),
-		safe_for_read(GPCMD_VERIFY_10),
-		safe_for_read(VERIFY_16),
-
-		/* Audio CD commands */
-		safe_for_read(GPCMD_PLAY_CD),
-		safe_for_read(GPCMD_PLAY_AUDIO_10),
-		safe_for_read(GPCMD_PLAY_AUDIO_MSF),
-		safe_for_read(GPCMD_PLAY_AUDIO_TI),
-		safe_for_read(GPCMD_PAUSE_RESUME),
-
-		/* CD/DVD data reading */
-		safe_for_read(GPCMD_READ_BUFFER_CAPACITY),
-		safe_for_read(GPCMD_READ_CD),
-		safe_for_read(GPCMD_READ_CD_MSF),
-		safe_for_read(GPCMD_READ_DISC_INFO),
-		safe_for_read(GPCMD_READ_CDVD_CAPACITY),
-		safe_for_read(GPCMD_READ_DVD_STRUCTURE),
-		safe_for_read(GPCMD_READ_HEADER),
-		safe_for_read(GPCMD_READ_TRACK_RZONE_INFO),
-		safe_for_read(GPCMD_READ_SUBCHANNEL),
-		safe_for_read(GPCMD_READ_TOC_PMA_ATIP),
-		safe_for_read(GPCMD_REPORT_KEY),
-		safe_for_read(GPCMD_SCAN),
-		safe_for_read(GPCMD_GET_CONFIGURATION),
-		safe_for_read(GPCMD_READ_FORMAT_CAPACITIES),
-		safe_for_read(GPCMD_GET_EVENT_STATUS_NOTIFICATION),
-		safe_for_read(GPCMD_GET_PERFORMANCE),
-		safe_for_read(GPCMD_SEEK),
-		safe_for_read(GPCMD_STOP_PLAY_SCAN),
-
-		/* Basic writing commands */
-		safe_for_write(WRITE_6),
-		safe_for_write(WRITE_10),
-		safe_for_write(WRITE_VERIFY),
-		safe_for_write(WRITE_12),
-		safe_for_write(WRITE_VERIFY_12),
-		safe_for_write(WRITE_16),
-		safe_for_write(WRITE_LONG),
-		safe_for_write(WRITE_LONG_2),
-		safe_for_write(ERASE),
-		safe_for_write(GPCMD_MODE_SELECT_10),
-		safe_for_write(MODE_SELECT),
-		safe_for_write(LOG_SELECT),
-		safe_for_write(GPCMD_BLANK),
-		safe_for_write(GPCMD_CLOSE_TRACK),
-		safe_for_write(GPCMD_FLUSH_CACHE),
-		safe_for_write(GPCMD_FORMAT_UNIT),
-		safe_for_write(GPCMD_REPAIR_RZONE_TRACK),
-		safe_for_write(GPCMD_RESERVE_RZONE_TRACK),
-		safe_for_write(GPCMD_SEND_DVD_STRUCTURE),
-		safe_for_write(GPCMD_SEND_EVENT),
-		safe_for_write(GPCMD_SEND_KEY),
-		safe_for_write(GPCMD_SEND_OPC),
-		safe_for_write(GPCMD_SEND_CUE_SHEET),
-		safe_for_write(GPCMD_SET_SPEED),
-		safe_for_write(GPCMD_PREVENT_ALLOW_MEDIUM_REMOVAL),
-		safe_for_write(GPCMD_LOAD_UNLOAD),
-		safe_for_write(GPCMD_SET_STREAMING),
-	};
-	unsigned char type = cmd_type[cmd[0]];
-
-	/* Anybody who can open the device can do a read-safe command */
-	if (type & CMD_READ_SAFE)
-		return 0;
-
-	/* Write-safe commands just require a writable open.. */
-	if (type & CMD_WRITE_SAFE) {
-		if (file->f_mode & FMODE_WRITE)
-			return 0;
-	}
-
-	/* And root can do any command.. */
-	if (capable(CAP_SYS_RAWIO))
-		return 0;
-
-	if (!type) {
-		cmd_type[cmd[0]] = CMD_WARNED;
-		printk(KERN_WARNING "scsi: unknown opcode 0x%02x\n", cmd[0]);
-	}
-
-	/* Otherwise fail it with an "Operation not permitted" */
-	return -EPERM;
-}
-
-static int sg_io(struct file *file, request_queue_t *q,
-		struct gendisk *bd_disk, struct sg_io_hdr *hdr)
-{
-	unsigned long start_time;
-	int writing = 0, ret = 0;
-	struct request *rq;
-	struct bio *bio;
-	char sense[SCSI_SENSE_BUFFERSIZE];
-	unsigned char cmd[BLK_MAX_CDB];
-
-	if (hdr->interface_id != 'S')
-		return -EINVAL;
-	if (hdr->cmd_len > BLK_MAX_CDB)
-		return -EINVAL;
-	if (copy_from_user(cmd, hdr->cmdp, hdr->cmd_len))
-		return -EFAULT;
-	if (verify_command(file, cmd))
-		return -EPERM;
-
-	if (hdr->dxfer_len > (q->max_sectors << 9))
-		return -EIO;
-
-	if (hdr->dxfer_len)
-		switch (hdr->dxfer_direction) {
-		default:
-			return -EINVAL;
-		case SG_DXFER_TO_FROM_DEV:
-		case SG_DXFER_TO_DEV:
-			writing = 1;
-			break;
-		case SG_DXFER_FROM_DEV:
-			break;
-		}
-
-	rq = blk_get_request(q, writing ? WRITE : READ, GFP_KERNEL);
-	if (!rq)
-		return -ENOMEM;
-
-	if (hdr->iovec_count) {
-		const int size = sizeof(struct sg_iovec) * hdr->iovec_count;
-		struct sg_iovec *iov;
-
-		iov = kmalloc(size, GFP_KERNEL);
-		if (!iov) {
-			ret = -ENOMEM;
-			goto out;
-		}
-
-		if (copy_from_user(iov, hdr->dxferp, size)) {
-			kfree(iov);
-			ret = -EFAULT;
-			goto out;
-		}
-
-		ret = blk_rq_map_user_iov(q, rq, iov, hdr->iovec_count);
-		kfree(iov);
-	} else if (hdr->dxfer_len)
-		ret = blk_rq_map_user(q, rq, hdr->dxferp, hdr->dxfer_len);
-
-	if (ret)
-		goto out;
-
-	/*
-	 * fill in request structure
-	 */
-	rq->cmd_len = hdr->cmd_len;
-	memcpy(rq->cmd, cmd, hdr->cmd_len);
-	if (sizeof(rq->cmd) != hdr->cmd_len)
-		memset(rq->cmd + hdr->cmd_len, 0, sizeof(rq->cmd) - hdr->cmd_len);
-
-	memset(sense, 0, sizeof(sense));
-	rq->sense = sense;
-	rq->sense_len = 0;
-
-	rq->flags |= REQ_BLOCK_PC;
-	bio = rq->bio;
-
-	/*
-	 * bounce this after holding a reference to the original bio, it's
-	 * needed for proper unmapping
-	 */
-	if (rq->bio)
-		blk_queue_bounce(q, &rq->bio);
-
-	rq->timeout = (hdr->timeout * HZ) / 1000;
-	if (!rq->timeout)
-		rq->timeout = q->sg_timeout;
-	if (!rq->timeout)
-		rq->timeout = BLK_DEFAULT_TIMEOUT;
-
-	start_time = jiffies;
-
-	/* ignore return value. All information is passed back to caller
-	 * (if he doesn't check that is his problem).
-	 * N.B. a non-zero SCSI status is _not_ necessarily an error.
-	 */
-	blk_execute_rq(q, bd_disk, rq, 0);
-
-	/* write to all output members */
-	hdr->status = 0xff & rq->errors;
-	hdr->masked_status = status_byte(rq->errors);
-	hdr->msg_status = msg_byte(rq->errors);
-	hdr->host_status = host_byte(rq->errors);
-	hdr->driver_status = driver_byte(rq->errors);
-	hdr->info = 0;
-	if (hdr->masked_status || hdr->host_status || hdr->driver_status)
-		hdr->info |= SG_INFO_CHECK;
-	hdr->resid = rq->data_len;
-	hdr->duration = ((jiffies - start_time) * 1000) / HZ;
-	hdr->sb_len_wr = 0;
-
-	if (rq->sense_len && hdr->sbp) {
-		int len = min((unsigned int) hdr->mx_sb_len, rq->sense_len);
-
-		if (!copy_to_user(hdr->sbp, rq->sense, len))
-			hdr->sb_len_wr = len;
-	}
-
-	if (blk_rq_unmap_user(bio, hdr->dxfer_len))
-		ret = -EFAULT;
-
-	/* may not have succeeded, but output values written to control
-	 * structure (struct sg_io_hdr).  */
-out:
-	blk_put_request(rq);
-	return ret;
-}
-
-#define OMAX_SB_LEN 16          /* For backward compatibility */
-
-static int sg_scsi_ioctl(struct file *file, request_queue_t *q,
-			 struct gendisk *bd_disk, Scsi_Ioctl_Command __user *sic)
-{
-	struct request *rq;
-	int err;
-	unsigned int in_len, out_len, bytes, opcode, cmdlen;
-	char *buffer = NULL, sense[SCSI_SENSE_BUFFERSIZE];
-
-	/*
-	 * get in an out lengths, verify they don't exceed a page worth of data
-	 */
-	if (get_user(in_len, &sic->inlen))
-		return -EFAULT;
-	if (get_user(out_len, &sic->outlen))
-		return -EFAULT;
-	if (in_len > PAGE_SIZE || out_len > PAGE_SIZE)
-		return -EINVAL;
-	if (get_user(opcode, sic->data))
-		return -EFAULT;
-
-	bytes = max(in_len, out_len);
-	if (bytes) {
-		buffer = kmalloc(bytes, q->bounce_gfp | GFP_USER| __GFP_NOWARN);
-		if (!buffer)
-			return -ENOMEM;
-
-		memset(buffer, 0, bytes);
-	}
-
-	rq = blk_get_request(q, in_len ? WRITE : READ, __GFP_WAIT);
-
-	cmdlen = COMMAND_SIZE(opcode);
-
-	/*
-	 * get command and data to send to device, if any
-	 */
-	err = -EFAULT;
-	rq->cmd_len = cmdlen;
-	if (copy_from_user(rq->cmd, sic->data, cmdlen))
-		goto error;
-
-	if (copy_from_user(buffer, sic->data + cmdlen, in_len))
-		goto error;
-
-	err = verify_command(file, rq->cmd);
-	if (err)
-		goto error;
-
-	switch (opcode) {
-		case SEND_DIAGNOSTIC:
-		case FORMAT_UNIT:
-			rq->timeout = FORMAT_UNIT_TIMEOUT;
-			break;
-		case START_STOP:
-			rq->timeout = START_STOP_TIMEOUT;
-			break;
-		case MOVE_MEDIUM:
-			rq->timeout = MOVE_MEDIUM_TIMEOUT;
-			break;
-		case READ_ELEMENT_STATUS:
-			rq->timeout = READ_ELEMENT_STATUS_TIMEOUT;
-			break;
-		case READ_DEFECT_DATA:
-			rq->timeout = READ_DEFECT_DATA_TIMEOUT;
-			break;
-		default:
-			rq->timeout = BLK_DEFAULT_TIMEOUT;
-			break;
-	}
-
-	memset(sense, 0, sizeof(sense));
-	rq->sense = sense;
-	rq->sense_len = 0;
-
-	rq->data = buffer;
-	rq->data_len = bytes;
-	rq->flags |= REQ_BLOCK_PC;
-
-	blk_execute_rq(q, bd_disk, rq, 0);
-	err = rq->errors & 0xff;	/* only 8 bit SCSI status */
-	if (err) {
-		if (rq->sense_len && rq->sense) {
-			bytes = (OMAX_SB_LEN > rq->sense_len) ?
-				rq->sense_len : OMAX_SB_LEN;
-			if (copy_to_user(sic->data, rq->sense, bytes))
-				err = -EFAULT;
-		}
-	} else {
-		if (copy_to_user(sic->data, buffer, out_len))
-			err = -EFAULT;
-	}
-	
-error:
-	kfree(buffer);
-	blk_put_request(rq);
-	return err;
-}
-
-int scsi_cmd_ioctl(struct file *file, struct gendisk *bd_disk, unsigned int cmd, void __user *arg)
-{
-	request_queue_t *q;
-	struct request *rq;
-	int close = 0, err;
-
-	q = bd_disk->queue;
-	if (!q)
-		return -ENXIO;
-
-	if (blk_get_queue(q))
-		return -ENXIO;
-
-	switch (cmd) {
-		/*
-		 * new sgv3 interface
-		 */
-		case SG_GET_VERSION_NUM:
-			err = sg_get_version(arg);
-			break;
-		case SCSI_IOCTL_GET_IDLUN:
-			err = scsi_get_idlun(q, arg);
-			break;
-		case SCSI_IOCTL_GET_BUS_NUMBER:
-			err = scsi_get_bus(q, arg);
-			break;
-		case SG_SET_TIMEOUT:
-			err = sg_set_timeout(q, arg);
-			break;
-		case SG_GET_TIMEOUT:
-			err = sg_get_timeout(q);
-			break;
-		case SG_GET_RESERVED_SIZE:
-			err = sg_get_reserved_size(q, arg);
-			break;
-		case SG_SET_RESERVED_SIZE:
-			err = sg_set_reserved_size(q, arg);
-			break;
-		case SG_EMULATED_HOST:
-			err = sg_emulated_host(q, arg);
-			break;
-		case SG_IO: {
-			struct sg_io_hdr hdr;
-
-			err = -EFAULT;
-			if (copy_from_user(&hdr, arg, sizeof(hdr)))
-				break;
-			err = sg_io(file, q, bd_disk, &hdr);
-			if (err == -EFAULT)
-				break;
-
-			if (copy_to_user(arg, &hdr, sizeof(hdr)))
-				err = -EFAULT;
-			break;
-		}
-		case CDROM_SEND_PACKET: {
-			struct cdrom_generic_command cgc;
-			struct sg_io_hdr hdr;
-
-			err = -EFAULT;
-			if (copy_from_user(&cgc, arg, sizeof(cgc)))
-				break;
-			cgc.timeout = clock_t_to_jiffies(cgc.timeout);
-			memset(&hdr, 0, sizeof(hdr));
-			hdr.interface_id = 'S';
-			hdr.cmd_len = sizeof(cgc.cmd);
-			hdr.dxfer_len = cgc.buflen;
-			err = 0;
-			switch (cgc.data_direction) {
-				case CGC_DATA_UNKNOWN:
-					hdr.dxfer_direction = SG_DXFER_UNKNOWN;
-					break;
-				case CGC_DATA_WRITE:
-					hdr.dxfer_direction = SG_DXFER_TO_DEV;
-					break;
-				case CGC_DATA_READ:
-					hdr.dxfer_direction = SG_DXFER_FROM_DEV;
-					break;
-				case CGC_DATA_NONE:
-					hdr.dxfer_direction = SG_DXFER_NONE;
-					break;
-				default:
-					err = -EINVAL;
-			}
-			if (err)
-				break;
-
-			hdr.dxferp = cgc.buffer;
-			hdr.sbp = cgc.sense;
-			if (hdr.sbp)
-				hdr.mx_sb_len = sizeof(struct request_sense);
-			hdr.timeout = cgc.timeout;
-			hdr.cmdp = ((struct cdrom_generic_command __user*) arg)->cmd;
-			hdr.cmd_len = sizeof(cgc.cmd);
-
-			err = sg_io(file, q, bd_disk, &hdr);
-			if (err == -EFAULT)
-				break;
-
-			if (hdr.status)
-				err = -EIO;
-
-			cgc.stat = err;
-			cgc.buflen = hdr.resid;
-			if (copy_to_user(arg, &cgc, sizeof(cgc)))
-				err = -EFAULT;
-
-			break;
-		}
-
-		/*
-		 * old junk scsi send command ioctl
-		 */
-		case SCSI_IOCTL_SEND_COMMAND:
-			printk(KERN_WARNING "program %s is using a deprecated SCSI ioctl, please convert it to SG_IO\n", current->comm);
-			err = -EINVAL;
-			if (!arg)
-				break;
-
-			err = sg_scsi_ioctl(file, q, bd_disk, arg);
-			break;
-		case CDROMCLOSETRAY:
-			close = 1;
-		case CDROMEJECT:
-			rq = blk_get_request(q, WRITE, __GFP_WAIT);
-			rq->flags |= REQ_BLOCK_PC;
-			rq->data = NULL;
-			rq->data_len = 0;
-			rq->timeout = BLK_DEFAULT_TIMEOUT;
-			memset(rq->cmd, 0, sizeof(rq->cmd));
-			rq->cmd[0] = GPCMD_START_STOP_UNIT;
-			rq->cmd[4] = 0x02 + (close != 0);
-			rq->cmd_len = 6;
-			err = blk_execute_rq(q, bd_disk, rq, 0);
-			blk_put_request(rq);
-			break;
-		default:
-			err = -ENOTTY;
-	}
-
-	blk_put_queue(q);
-	return err;
-}
-
-EXPORT_SYMBOL(scsi_cmd_ioctl);