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Commit 613be1f6 authored by Bart Van Assche's avatar Bart Van Assche Committed by James Bottomley
Browse files

[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: default avatarBart Van Assche <bvanassche@acm.org>
Reviewed-by: default avatarTejun Heo <tj@kernel.org>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 04796336

drivers/scsi/scsi_lib.c

+3 −11
Original line number Diff line number Diff line
@@ -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)