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authorBart Van Assche <bvanassche@acm.org>2014-02-21 02:20:56 +0400
committerJames Bottomley <JBottomley@Parallels.com>2014-03-15 21:19:25 +0400
commit613be1f626e602c6744101a003e8fc5c180e1af9 (patch)
tree4c78a6ed1be7b817fdb7a233dd1d346e786f2f31 /drivers/scsi
parent0479633686d370303e3430256ace4bd5f7f138dc (diff)
downloadlinux-613be1f626e602c6744101a003e8fc5c180e1af9.tar.xz
[SCSI] remove a useless get/put_device pair in scsi_request_fn
SCSI devices may only be removed by calling scsi_remove_device(). That function must invoke blk_cleanup_queue() before the final put of sdev->sdev_gendev. Since blk_cleanup_queue() waits for the block queue to drain and then tears it down, scsi_request_fn cannot be active anymore after blk_cleanup_queue() has returned and hence the get_device()/put_device() pair in scsi_request_fn is unnecessary. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Tejun Heo <tj@kernel.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/scsi_lib.c14
1 files changed, 3 insertions, 11 deletions
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 007e979fa437..f8a8765a7979 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1565,16 +1565,14 @@ static void scsi_softirq_done(struct request *rq)
* Lock status: IO request lock assumed to be held when called.
*/
static void scsi_request_fn(struct request_queue *q)
+ __releases(q->queue_lock)
+ __acquires(q->queue_lock)
{
struct scsi_device *sdev = q->queuedata;
struct Scsi_Host *shost;
struct scsi_cmnd *cmd;
struct request *req;
- if(!get_device(&sdev->sdev_gendev))
- /* We must be tearing the block queue down already */
- return;
-
/*
* To start with, we keep looping until the queue is empty, or until
* the host is no longer able to accept any more requests.
@@ -1663,7 +1661,7 @@ static void scsi_request_fn(struct request_queue *q)
goto out_delay;
}
- goto out;
+ return;
not_ready:
spin_unlock_irq(shost->host_lock);
@@ -1682,12 +1680,6 @@ static void scsi_request_fn(struct request_queue *q)
out_delay:
if (sdev->device_busy == 0)
blk_delay_queue(q, SCSI_QUEUE_DELAY);
-out:
- /* must be careful here...if we trigger the ->remove() function
- * we cannot be holding the q lock */
- spin_unlock_irq(q->queue_lock);
- put_device(&sdev->sdev_gendev);
- spin_lock_irq(q->queue_lock);
}
u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost)