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Commit 818c5f3b authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm: fix a couple locking issues with use of block interfaces 



old_stop_queue() was checking blk_queue_stopped() without holding the
q->queue_lock.

dm_requeue_original_request() needed to check blk_queue_stopped(), with
q->queue_lock held, before calling blk_mq_kick_requeue_list().  And a
side-effect of that change is start_queue() must also call
blk_mq_kick_requeue_list().

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 1c357a1e

drivers/md/dm.c

+21 −7
Original line number Diff line number Diff line
@@ -1215,6 +1215,18 @@ static void old_requeue_request(struct request *rq) 
	spin_unlock_irqrestore(q->queue_lock, flags);

}



static void dm_mq_requeue_request(struct request *rq)

{

	struct request_queue *q = rq->q;

	unsigned long flags;



	blk_mq_requeue_request(rq);

	spin_lock_irqsave(q->queue_lock, flags);

	if (!blk_queue_stopped(q))

		blk_mq_kick_requeue_list(q);

	spin_unlock_irqrestore(q->queue_lock, flags);

}



static void dm_requeue_original_request(struct mapped_device *md,

					struct request *rq)

{
@@ -1225,10 +1237,8 @@ static void dm_requeue_original_request(struct mapped_device *md, 
	rq_end_stats(md, rq);

	if (!rq->q->mq_ops)

		old_requeue_request(rq);

	else {

		blk_mq_requeue_request(rq);

		blk_mq_kick_requeue_list(rq->q);

	}

	else

		dm_mq_requeue_request(rq);



	rq_completed(md, rw, false);

}
@@ -1237,10 +1247,12 @@ static void old_stop_queue(struct request_queue *q) 
{

	unsigned long flags;



	if (blk_queue_stopped(q))

	spin_lock_irqsave(q->queue_lock, flags);

	if (blk_queue_stopped(q)) {

		spin_unlock_irqrestore(q->queue_lock, flags);

		return;

	}



	spin_lock_irqsave(q->queue_lock, flags);

	blk_stop_queue(q);

	spin_unlock_irqrestore(q->queue_lock, flags);

}
@@ -1267,8 +1279,10 @@ static void start_queue(struct request_queue *q) 
{

	if (!q->mq_ops)

		old_start_queue(q);

	else

	else {

		blk_mq_start_stopped_hw_queues(q, true);

		blk_mq_kick_requeue_list(q);

	}

}



static void dm_done(struct request *clone, int error, bool mapped)