From 75ad23bc0fcb4f992a5d06982bf0857ab1738e9e Mon Sep 17 00:00:00 2001 From: Nick Piggin Date: Tue, 29 Apr 2008 14:48:33 +0200 Subject: block: make queue flags non-atomic We can save some atomic ops in the IO path, if we clearly define the rules of how to modify the queue flags. Signed-off-by: Jens Axboe --- drivers/scsi/scsi_debug.c | 2 +- drivers/scsi/scsi_lib.c | 31 ++++++++++++++++++------------- drivers/scsi/scsi_transport_sas.c | 3 +-- 3 files changed, 20 insertions(+), 16 deletions(-) (limited to 'drivers/scsi') diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index 07103c399fe0..f6600bfb5bde 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -1773,7 +1773,7 @@ static int scsi_debug_slave_alloc(struct scsi_device *sdp) if (SCSI_DEBUG_OPT_NOISE & scsi_debug_opts) printk(KERN_INFO "scsi_debug: slave_alloc <%u %u %u %u>\n", sdp->host->host_no, sdp->channel, sdp->id, sdp->lun); - set_bit(QUEUE_FLAG_BIDI, &sdp->request_queue->queue_flags); + queue_flag_set_unlocked(QUEUE_FLAG_BIDI, sdp->request_queue); return 0; } diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 67f412bb4974..d545ad1cf47a 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -536,6 +536,9 @@ static void scsi_run_queue(struct request_queue *q) !shost->host_blocked && !shost->host_self_blocked && !((shost->can_queue > 0) && (shost->host_busy >= shost->can_queue))) { + + int flagset; + /* * As long as shost is accepting commands and we have * starved queues, call blk_run_queue. scsi_request_fn @@ -549,19 +552,20 @@ static void scsi_run_queue(struct request_queue *q) sdev = list_entry(shost->starved_list.next, struct scsi_device, starved_entry); list_del_init(&sdev->starved_entry); - spin_unlock_irqrestore(shost->host_lock, flags); - + spin_unlock(shost->host_lock); + + spin_lock(sdev->request_queue->queue_lock); + flagset = test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) && + !test_bit(QUEUE_FLAG_REENTER, + &sdev->request_queue->queue_flags); + if (flagset) + queue_flag_set(QUEUE_FLAG_REENTER, sdev->request_queue); + __blk_run_queue(sdev->request_queue); + if (flagset) + queue_flag_clear(QUEUE_FLAG_REENTER, sdev->request_queue); + spin_unlock(sdev->request_queue->queue_lock); - if (test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) && - !test_and_set_bit(QUEUE_FLAG_REENTER, - &sdev->request_queue->queue_flags)) { - blk_run_queue(sdev->request_queue); - clear_bit(QUEUE_FLAG_REENTER, - &sdev->request_queue->queue_flags); - } else - blk_run_queue(sdev->request_queue); - - spin_lock_irqsave(shost->host_lock, flags); + spin_lock(shost->host_lock); if (unlikely(!list_empty(&sdev->starved_entry))) /* * sdev lost a race, and was put back on the @@ -1585,8 +1589,9 @@ struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); + /* New queue, no concurrency on queue_flags */ if (!shost->use_clustering) - clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); + queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q); /* * set a reasonable default alignment on word boundaries: the diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c index 7899e3dda9bf..f4461d35ffb9 100644 --- a/drivers/scsi/scsi_transport_sas.c +++ b/drivers/scsi/scsi_transport_sas.c @@ -248,8 +248,7 @@ static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy) else q->queuedata = shost; - set_bit(QUEUE_FLAG_BIDI, &q->queue_flags); - + queue_flag_set_unlocked(QUEUE_FLAG_BIDI, q); return 0; } -- cgit v1.2.3 From 4917fa292558593d36b2880977ea206f7727dbe5 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Tue, 29 Apr 2008 09:54:35 +0200 Subject: block: no need to initialize rq->cmd in prepare_flush_fn hook The block layer initializes rq->cmd (queue_flush calls rq_init) so prepare_flush_fn hooks don't need to do that. The purpose of this patch is to remove sizeof(rq->cmd), as a preparation for large command support, which changes rq->cmd from the static array to a pointer. sizeof(rq->cmd) will not make sense. Signed-off-by: FUJITA Tomonori Cc: Geert Uytterhoeven Cc: James Bottomley Cc: Jens Axboe Signed-off-by: Jens Axboe --- drivers/block/ps3disk.c | 1 - drivers/scsi/sd.c | 1 - 2 files changed, 2 deletions(-) (limited to 'drivers/scsi') diff --git a/drivers/block/ps3disk.c b/drivers/block/ps3disk.c index 78e9ea73a31a..d797e209951d 100644 --- a/drivers/block/ps3disk.c +++ b/drivers/block/ps3disk.c @@ -405,7 +405,6 @@ static void ps3disk_prepare_flush(struct request_queue *q, struct request *req) dev_dbg(&dev->sbd.core, "%s:%u\n", __func__, __LINE__); - memset(req->cmd, 0, sizeof(req->cmd)); req->cmd_type = REQ_TYPE_FLUSH; } diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 3cea17dd5dba..01cefbb2d539 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -860,7 +860,6 @@ static int sd_sync_cache(struct scsi_disk *sdkp) static void sd_prepare_flush(struct request_queue *q, struct request *rq) { - memset(rq->cmd, 0, sizeof(rq->cmd)); rq->cmd_type = REQ_TYPE_BLOCK_PC; rq->timeout = SD_TIMEOUT; rq->cmd[0] = SYNCHRONIZE_CACHE; -- cgit v1.2.3 From 4f54eec8311c3325888c29ce8e4496daf4dbe624 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Tue, 29 Apr 2008 09:54:37 +0200 Subject: block: use blk_rq_init() to initialize the request Any path needs to call it to initialize the request. This is a preparation for large command support, which needs to initialize the request in a proper way (that is, just doing a memset() will not work). Signed-off-by: FUJITA Tomonori Cc: Jens Axboe Signed-off-by: Jens Axboe --- drivers/block/nbd.c | 1 + drivers/block/paride/pd.c | 4 +--- drivers/scsi/scsi_error.c | 1 + 3 files changed, 3 insertions(+), 3 deletions(-) (limited to 'drivers/scsi') diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 60cc54368b66..f75bda16a1fc 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -537,6 +537,7 @@ static int nbd_ioctl(struct inode *inode, struct file *file, switch (cmd) { case NBD_DISCONNECT: printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); + blk_rq_init(NULL, &sreq); sreq.cmd_type = REQ_TYPE_SPECIAL; nbd_cmd(&sreq) = NBD_CMD_DISC; /* diff --git a/drivers/block/paride/pd.c b/drivers/block/paride/pd.c index df819f8a95a6..570f3b70dce7 100644 --- a/drivers/block/paride/pd.c +++ b/drivers/block/paride/pd.c @@ -716,10 +716,8 @@ static int pd_special_command(struct pd_unit *disk, struct request rq; int err = 0; - memset(&rq, 0, sizeof(rq)); - rq.errors = 0; + blk_rq_init(NULL, &rq); rq.rq_disk = disk->gd; - rq.ref_count = 1; rq.end_io_data = &wait; rq.end_io = blk_end_sync_rq; blk_insert_request(disk->gd->queue, &rq, 0, func); diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 221f31e36d26..1eaba6cd80f4 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -1771,6 +1771,7 @@ scsi_reset_provider(struct scsi_device *dev, int flag) unsigned long flags; int rtn; + blk_rq_init(NULL, &req); scmd->request = &req; memset(&scmd->eh_timeout, 0, sizeof(scmd->eh_timeout)); -- cgit v1.2.3