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[SCSI] remove a useless get/put_device pair in scsi_request_fn

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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>
This commit is contained in:
Bart Van Assche 2014-02-20 14:20:56 -08:00 committed by James Bottomley
parent 0479633686
commit 613be1f626
1 changed files with 3 additions and 11 deletions
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14
drivers/scsi/scsi_lib.c
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@ -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)