diff options
| -rw-r--r-- | block/bsg.c | 460 |
1 files changed, 6 insertions, 454 deletions
diff --git a/block/bsg.c b/block/bsg.c index 66602c489956..0d2e9bf6208b 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -13,11 +13,9 @@ #include <linux/init.h> #include <linux/file.h> #include <linux/blkdev.h> -#include <linux/poll.h> #include <linux/cdev.h> #include <linux/jiffies.h> #include <linux/percpu.h> -#include <linux/uio.h> #include <linux/idr.h> #include <linux/bsg.h> #include <linux/slab.h> @@ -38,21 +36,10 @@ struct bsg_device { struct request_queue *queue; spinlock_t lock; - struct list_head busy_list; - struct list_head done_list; struct hlist_node dev_list; atomic_t ref_count; - int queued_cmds; - int done_cmds; - wait_queue_head_t wq_done; - wait_queue_head_t wq_free; char name[20]; int max_queue; - unsigned long flags; -}; - -enum { - BSG_F_BLOCK = 1, }; #define BSG_DEFAULT_CMDS 64 @@ -67,64 +54,6 @@ static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; static struct class *bsg_class; static int bsg_major; -static struct kmem_cache *bsg_cmd_cachep; - -/* - * our internal command type - */ -struct bsg_command { - struct bsg_device *bd; - struct list_head list; - struct request *rq; - struct bio *bio; - struct bio *bidi_bio; - int err; - struct sg_io_v4 hdr; -}; - -static void bsg_free_command(struct bsg_command *bc) -{ - struct bsg_device *bd = bc->bd; - unsigned long flags; - - kmem_cache_free(bsg_cmd_cachep, bc); - - spin_lock_irqsave(&bd->lock, flags); - bd->queued_cmds--; - spin_unlock_irqrestore(&bd->lock, flags); - - wake_up(&bd->wq_free); -} - -static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) -{ - struct bsg_command *bc = ERR_PTR(-EINVAL); - - spin_lock_irq(&bd->lock); - - if (bd->queued_cmds >= bd->max_queue) - goto out; - - bd->queued_cmds++; - spin_unlock_irq(&bd->lock); - - bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); - if (unlikely(!bc)) { - spin_lock_irq(&bd->lock); - bd->queued_cmds--; - bc = ERR_PTR(-ENOMEM); - goto out; - } - - bc->bd = bd; - INIT_LIST_HEAD(&bc->list); - bsg_dbg(bd, "returning free cmd %p\n", bc); - return bc; -out: - spin_unlock_irq(&bd->lock); - return bc; -} - static inline struct hlist_head *bsg_dev_idx_hash(int index) { return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; @@ -287,101 +216,6 @@ out: return ERR_PTR(ret); } -/* - * async completion call-back from the block layer, when scsi/ide/whatever - * calls end_that_request_last() on a request - */ -static void bsg_rq_end_io(struct request *rq, blk_status_t status) -{ - struct bsg_command *bc = rq->end_io_data; - struct bsg_device *bd = bc->bd; - unsigned long flags; - - bsg_dbg(bd, "finished rq %p bc %p, bio %p\n", - rq, bc, bc->bio); - - bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); - - spin_lock_irqsave(&bd->lock, flags); - list_move_tail(&bc->list, &bd->done_list); - bd->done_cmds++; - spin_unlock_irqrestore(&bd->lock, flags); - - wake_up(&bd->wq_done); -} - -/* - * do final setup of a 'bc' and submit the matching 'rq' to the block - * layer for io - */ -static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, - struct bsg_command *bc, struct request *rq) -{ - int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); - - /* - * add bc command to busy queue and submit rq for io - */ - bc->rq = rq; - bc->bio = rq->bio; - if (rq->next_rq) - bc->bidi_bio = rq->next_rq->bio; - bc->hdr.duration = jiffies; - spin_lock_irq(&bd->lock); - list_add_tail(&bc->list, &bd->busy_list); - spin_unlock_irq(&bd->lock); - - bsg_dbg(bd, "queueing rq %p, bc %p\n", rq, bc); - - rq->end_io_data = bc; - blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); -} - -static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) -{ - struct bsg_command *bc = NULL; - - spin_lock_irq(&bd->lock); - if (bd->done_cmds) { - bc = list_first_entry(&bd->done_list, struct bsg_command, list); - list_del(&bc->list); - bd->done_cmds--; - } - spin_unlock_irq(&bd->lock); - - return bc; -} - -/* - * Get a finished command from the done list - */ -static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) -{ - struct bsg_command *bc; - int ret; - - do { - bc = bsg_next_done_cmd(bd); - if (bc) - break; - - if (!test_bit(BSG_F_BLOCK, &bd->flags)) { - bc = ERR_PTR(-EAGAIN); - break; - } - - ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); - if (ret) { - bc = ERR_PTR(-ERESTARTSYS); - break; - } - } while (1); - - bsg_dbg(bd, "returning done %p\n", bc); - - return bc; -} - static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, struct bio *bio, struct bio *bidi_bio) { @@ -400,234 +234,6 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, return ret; } -static bool bsg_complete(struct bsg_device *bd) -{ - bool ret = false; - bool spin; - - do { - spin_lock_irq(&bd->lock); - - BUG_ON(bd->done_cmds > bd->queued_cmds); - - /* - * All commands consumed. - */ - if (bd->done_cmds == bd->queued_cmds) - ret = true; - - spin = !test_bit(BSG_F_BLOCK, &bd->flags); - - spin_unlock_irq(&bd->lock); - } while (!ret && spin); - - return ret; -} - -static int bsg_complete_all_commands(struct bsg_device *bd) -{ - struct bsg_command *bc; - int ret, tret; - - bsg_dbg(bd, "entered\n"); - - /* - * wait for all commands to complete - */ - io_wait_event(bd->wq_done, bsg_complete(bd)); - - /* - * discard done commands - */ - ret = 0; - do { - spin_lock_irq(&bd->lock); - if (!bd->queued_cmds) { - spin_unlock_irq(&bd->lock); - break; - } - spin_unlock_irq(&bd->lock); - - bc = bsg_get_done_cmd(bd); - if (IS_ERR(bc)) - break; - - tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, - bc->bidi_bio); - if (!ret) - ret = tret; - - bsg_free_command(bc); - } while (1); - - return ret; -} - -static int -__bsg_read(char __user *buf, size_t count, struct bsg_device *bd, - const struct iovec *iov, ssize_t *bytes_read) -{ - struct bsg_command *bc; - int nr_commands, ret; - - if (count % sizeof(struct sg_io_v4)) - return -EINVAL; - - ret = 0; - nr_commands = count / sizeof(struct sg_io_v4); - while (nr_commands) { - bc = bsg_get_done_cmd(bd); - if (IS_ERR(bc)) { - ret = PTR_ERR(bc); - break; - } - - /* - * this is the only case where we need to copy data back - * after completing the request. so do that here, - * bsg_complete_work() cannot do that for us - */ - ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, - bc->bidi_bio); - - if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) - ret = -EFAULT; - - bsg_free_command(bc); - - if (ret) - break; - - buf += sizeof(struct sg_io_v4); - *bytes_read += sizeof(struct sg_io_v4); - nr_commands--; - } - - return ret; -} - -static inline void bsg_set_block(struct bsg_device *bd, struct file *file) -{ - if (file->f_flags & O_NONBLOCK) - clear_bit(BSG_F_BLOCK, &bd->flags); - else - set_bit(BSG_F_BLOCK, &bd->flags); -} - -/* - * Check if the error is a "real" error that we should return. - */ -static inline int err_block_err(int ret) -{ - if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) - return 1; - - return 0; -} - -static ssize_t -bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) -{ - struct bsg_device *bd = file->private_data; - int ret; - ssize_t bytes_read; - - bsg_dbg(bd, "read %zd bytes\n", count); - - bsg_set_block(bd, file); - - bytes_read = 0; - ret = __bsg_read(buf, count, bd, NULL, &bytes_read); - *ppos = bytes_read; - - if (!bytes_read || err_block_err(ret)) - bytes_read = ret; - - return bytes_read; -} - -static int __bsg_write(struct bsg_device *bd, const char __user *buf, - size_t count, ssize_t *bytes_written, fmode_t mode) -{ - struct bsg_command *bc; - struct request *rq; - int ret, nr_commands; - - if (count % sizeof(struct sg_io_v4)) - return -EINVAL; - - nr_commands = count / sizeof(struct sg_io_v4); - rq = NULL; - bc = NULL; - ret = 0; - while (nr_commands) { - struct request_queue *q = bd->queue; - - bc = bsg_alloc_command(bd); - if (IS_ERR(bc)) { - ret = PTR_ERR(bc); - bc = NULL; - break; - } - - if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { - ret = -EFAULT; - break; - } - - /* - * get a request, fill in the blanks, and add to request queue - */ - rq = bsg_map_hdr(bd->queue, &bc->hdr, mode); - if (IS_ERR(rq)) { - ret = PTR_ERR(rq); - rq = NULL; - break; - } - - bsg_add_command(bd, q, bc, rq); - bc = NULL; - rq = NULL; - nr_commands--; - buf += sizeof(struct sg_io_v4); - *bytes_written += sizeof(struct sg_io_v4); - } - - if (bc) - bsg_free_command(bc); - - return ret; -} - -static ssize_t -bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) -{ - struct bsg_device *bd = file->private_data; - ssize_t bytes_written; - int ret; - - bsg_dbg(bd, "write %zd bytes\n", count); - - if (unlikely(uaccess_kernel())) - return -EINVAL; - - bsg_set_block(bd, file); - - bytes_written = 0; - ret = __bsg_write(bd, buf, count, &bytes_written, file->f_mode); - - *ppos = bytes_written; - - /* - * return bytes written on non-fatal errors - */ - if (!bytes_written || err_block_err(ret)) - bytes_written = ret; - - bsg_dbg(bd, "returning %zd\n", bytes_written); - return bytes_written; -} - static struct bsg_device *bsg_alloc_device(void) { struct bsg_device *bd; @@ -637,29 +243,20 @@ static struct bsg_device *bsg_alloc_device(void) return NULL; spin_lock_init(&bd->lock); - bd->max_queue = BSG_DEFAULT_CMDS; - - INIT_LIST_HEAD(&bd->busy_list); - INIT_LIST_HEAD(&bd->done_list); INIT_HLIST_NODE(&bd->dev_list); - - init_waitqueue_head(&bd->wq_free); - init_waitqueue_head(&bd->wq_done); return bd; } static int bsg_put_device(struct bsg_device *bd) { - int ret = 0, do_free; struct request_queue *q = bd->queue; mutex_lock(&bsg_mutex); - do_free = atomic_dec_and_test(&bd->ref_count); - if (!do_free) { + if (!atomic_dec_and_test(&bd->ref_count)) { mutex_unlock(&bsg_mutex); - goto out; + return 0; } hlist_del(&bd->dev_list); @@ -670,20 +267,9 @@ static int bsg_put_device(struct bsg_device *bd) /* * close can always block */ - set_bit(BSG_F_BLOCK, &bd->flags); - - /* - * correct error detection baddies here again. it's the responsibility - * of the app to properly reap commands before close() if it wants - * fool-proof error detection - */ - ret = bsg_complete_all_commands(bd); - kfree(bd); -out: - if (do_free) - blk_put_queue(q); - return ret; + blk_put_queue(q); + return 0; } static struct bsg_device *bsg_add_device(struct inode *inode, @@ -706,8 +292,6 @@ static struct bsg_device *bsg_add_device(struct inode *inode, bd->queue = rq; - bsg_set_block(bd, file); - atomic_set(&bd->ref_count, 1); hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); @@ -781,24 +365,6 @@ static int bsg_release(struct inode *inode, struct file *file) return bsg_put_device(bd); } -static __poll_t bsg_poll(struct file *file, poll_table *wait) -{ - struct bsg_device *bd = file->private_data; - __poll_t mask = 0; - - poll_wait(file, &bd->wq_done, wait); - poll_wait(file, &bd->wq_free, wait); - - spin_lock_irq(&bd->lock); - if (!list_empty(&bd->done_list)) - mask |= EPOLLIN | EPOLLRDNORM; - if (bd->queued_cmds < bd->max_queue) - mask |= EPOLLOUT; - spin_unlock_irq(&bd->lock); - - return mask; -} - static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct bsg_device *bd = file->private_data; @@ -872,9 +438,6 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) } static const struct file_operations bsg_fops = { - .read = bsg_read, - .write = bsg_write, - .poll = bsg_poll, .open = bsg_open, .release = bsg_release, .unlocked_ioctl = bsg_ioctl, @@ -979,21 +542,12 @@ static int __init bsg_init(void) int ret, i; dev_t devid; - bsg_cmd_cachep = kmem_cache_create("bsg_cmd", - sizeof(struct bsg_command), 0, 0, NULL); - if (!bsg_cmd_cachep) { - printk(KERN_ERR "bsg: failed creating slab cache\n"); - return -ENOMEM; - } - for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) INIT_HLIST_HEAD(&bsg_device_list[i]); bsg_class = class_create(THIS_MODULE, "bsg"); - if (IS_ERR(bsg_class)) { - ret = PTR_ERR(bsg_class); - goto destroy_kmemcache; - } + if (IS_ERR(bsg_class)) + return PTR_ERR(bsg_class); bsg_class->devnode = bsg_devnode; ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); @@ -1014,8 +568,6 @@ unregister_chrdev: unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); destroy_bsg_class: class_destroy(bsg_class); -destroy_kmemcache: - kmem_cache_destroy(bsg_cmd_cachep); return ret; } |