diff options
Diffstat (limited to 'drivers/scsi/scsi_lib.c')
-rw-r--r-- | drivers/scsi/scsi_lib.c | 50 |
1 files changed, 28 insertions, 22 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index d0bd7e0..1ddf0fb 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -302,9 +302,7 @@ void scsi_device_unbusy(struct scsi_device *sdev) spin_unlock_irqrestore(shost->host_lock, flags); } - spin_lock_irqsave(sdev->request_queue->queue_lock, flags); - sdev->device_busy--; - spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); + atomic_dec(&sdev->device_busy); } /* @@ -355,9 +353,9 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev) static inline int scsi_device_is_busy(struct scsi_device *sdev) { - if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked) + if (atomic_read(&sdev->device_busy) >= sdev->queue_depth || + sdev->device_blocked) return 1; - return 0; } @@ -1204,7 +1202,7 @@ scsi_prep_return(struct request_queue *q, struct request *req, int ret) * queue must be restarted, so we schedule a callback to happen * shortly. */ - if (sdev->device_busy == 0) + if (atomic_read(&sdev->device_busy) == 0) blk_delay_queue(q, SCSI_QUEUE_DELAY); break; default: @@ -1255,26 +1253,33 @@ static void scsi_unprep_fn(struct request_queue *q, struct request *req) static inline int scsi_dev_queue_ready(struct request_queue *q, struct scsi_device *sdev) { - if (sdev->device_busy == 0 && sdev->device_blocked) { + unsigned int busy; + + busy = atomic_inc_return(&sdev->device_busy) - 1; + if (sdev->device_blocked) { + if (busy) + goto out_dec; + /* * unblock after device_blocked iterates to zero */ - if (--sdev->device_blocked == 0) { - SCSI_LOG_MLQUEUE(3, - sdev_printk(KERN_INFO, sdev, - "unblocking device at zero depth\n")); - } else { + if (--sdev->device_blocked != 0) { blk_delay_queue(q, SCSI_QUEUE_DELAY); - return 0; + goto out_dec; } + SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev, + "unblocking device at zero depth\n")); } - if (scsi_device_is_busy(sdev)) - return 0; + + if (busy >= sdev->queue_depth) + goto out_dec; return 1; +out_dec: + atomic_dec(&sdev->device_busy); + return 0; } - /* * scsi_target_queue_ready: checks if there we can send commands to target * @sdev: scsi device on starget to check. @@ -1448,7 +1453,7 @@ static void scsi_kill_request(struct request *req, struct request_queue *q) * bump busy counts. To bump the counters, we need to dance * with the locks as normal issue path does. */ - sdev->device_busy++; + atomic_inc(&sdev->device_busy); atomic_inc(&shost->host_busy); atomic_inc(&starget->target_busy); @@ -1544,7 +1549,7 @@ static void scsi_request_fn(struct request_queue *q) * accept it. */ req = blk_peek_request(q); - if (!req || !scsi_dev_queue_ready(q, sdev)) + if (!req) break; if (unlikely(!scsi_device_online(sdev))) { @@ -1554,13 +1559,14 @@ static void scsi_request_fn(struct request_queue *q) continue; } + if (!scsi_dev_queue_ready(q, sdev)) + break; /* * Remove the request from the request list. */ if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) blk_start_request(req); - sdev->device_busy++; spin_unlock_irq(q->queue_lock); cmd = req->special; @@ -1630,9 +1636,9 @@ static void scsi_request_fn(struct request_queue *q) */ spin_lock_irq(q->queue_lock); blk_requeue_request(q, req); - sdev->device_busy--; + atomic_dec(&sdev->device_busy); out_delay: - if (sdev->device_busy == 0 && !scsi_device_blocked(sdev)) + if (atomic_read(&sdev->device_busy) && !scsi_device_blocked(sdev)) blk_delay_queue(q, SCSI_QUEUE_DELAY); } @@ -2371,7 +2377,7 @@ scsi_device_quiesce(struct scsi_device *sdev) return err; scsi_run_queue(sdev->request_queue); - while (sdev->device_busy) { + while (atomic_read(&sdev->device_busy)) { msleep_interruptible(200); scsi_run_queue(sdev->request_queue); } |