[PATCH] [PATCH] scsi: race in checking sdev->device_busy

[Jens Axboe]

Save some code, create a new out label for the path that already checks
the busy count and delays the queue if necessary.

Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
---
 drivers/scsi/scsi_lib.c |   11 ++++-------
 1 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index fce5e2f..3ffa35d 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1509,12 +1509,9 @@ static void scsi_request_fn(struct request_queue *q)
 		 * Dispatch the command to the low-level driver.
 		 */
 		rtn = scsi_dispatch_cmd(cmd);
-		if (rtn) {
-			if (sdev->device_busy == 0)
-				blk_delay_queue(q, SCSI_QUEUE_DELAY);
-			goto out_nolock;
-		}
 		spin_lock_irq(q->queue_lock);
+		if (rtn)
+			goto out_delay;
 	}
 
 	goto out;
@@ -1533,13 +1530,13 @@ static void scsi_request_fn(struct request_queue *q)
 	spin_lock_irq(q->queue_lock);
 	blk_requeue_request(q, req);
 	sdev->device_busy--;
+out_delay:
 	if (sdev->device_busy == 0)
 		blk_delay_queue(q, SCSI_QUEUE_DELAY);
- out:
+out:
 	/* must be careful here...if we trigger the ->remove() function
 	 * we cannot be holding the q lock */
 	spin_unlock_irq(q->queue_lock);
- out_nolock:
 	put_device(&sdev->sdev_gendev);
 	spin_lock_irq(q->queue_lock);
 }
-- 
1.5.0.rc0.gd222


-- 
Jens Axboe

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