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Commit 481a7d64 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

block: fix drain_all condition in blk_drain_queue() 



When trying to drain all requests, blk_drain_queue() checked only
q->rq.count[]; however, this only tracks REQ_ALLOCED requests.  This
patch updates blk_drain_queue() such that it looks at all the counters
and queues so that request_queue is actually empty on completion.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 34f6055c

block/blk-core.c

+18 −6
Original line number Diff line number Diff line
@@ -358,7 +358,8 @@ EXPORT_SYMBOL(blk_put_queue); 
void blk_drain_queue(struct request_queue *q, bool drain_all)

{

	while (true) {

		int nr_rqs;

		bool drain = false;

		int i;



		spin_lock_irq(q->queue_lock);
@@ -368,14 +369,25 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) 


		__blk_run_queue(q);



		if (drain_all)

			nr_rqs = q->rq.count[0] + q->rq.count[1];

		else

			nr_rqs = q->rq.elvpriv;

		drain |= q->rq.elvpriv;



		/*

		 * Unfortunately, requests are queued at and tracked from

		 * multiple places and there's no single counter which can

		 * be drained.  Check all the queues and counters.

		 */

		if (drain_all) {

			drain |= !list_empty(&q->queue_head);

			for (i = 0; i < 2; i++) {

				drain |= q->rq.count[i];

				drain |= q->in_flight[i];

				drain |= !list_empty(&q->flush_queue[i]);

			}

		}



		spin_unlock_irq(q->queue_lock);



		if (!nr_rqs)

		if (!drain)

			break;

		msleep(10);

	}