block: drain queue before waiting for q_usage_counter becoming zero (454be724) · Commits · 戴 / test

Now we track legacy requests with .q_usage_counter in commit ("block: Make q_usage_counter also track legacy requests"), but that commit never runs and drains legacy queue before waiting for this counter becoming zero, then IO hang is caused in the test of pulling disk during IO. This patch fixes the issue by draining requests before waiting for q_usage_counter becoming zero, both Mauricio and chenxiang reported this issue, and observed that it can be fixed by this patch. Link: https://marc.info/?l=linux-block&m=151192424731797&w=2 Fixes: ("block: Make q_usage_counter also track legacy requests") Cc: Wen Xiong <wenxiong@us.ibm.com> Tested-by:

"chenxiang (M)" <chenxiang66@hisilicon.com> Tested-by:

Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> Signed-off-by:

Ming Lei <ming.lei@redhat.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

block/blk-core.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -562,6 +562,13 @@ static void __blk_drain_queue(struct request_queue *q, bool drain_all)
		}
		}

		void blk_drain_queue(struct request_queue *q)
		{
		spin_lock_irq(q->queue_lock);
		__blk_drain_queue(q, true);
		spin_unlock_irq(q->queue_lock);
		}

		/**
		* blk_queue_bypass_start - enter queue bypass mode
		* @q: queue of interest
		@@ -689,8 +696,6 @@ void blk_cleanup_queue(struct request_queue *q)
		*/
		blk_freeze_queue(q);
		spin_lock_irq(lock);
		if (!q->mq_ops)
		__blk_drain_queue(q, true);
		queue_flag_set(QUEUE_FLAG_DEAD, q);
		spin_unlock_irq(lock);

block/blk-mq.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -161,6 +161,8 @@ void blk_freeze_queue(struct request_queue *q)
		* exported to drivers as the only user for unfreeze is blk_mq.
		*/
		blk_freeze_queue_start(q);
		if (!q->mq_ops)
		blk_drain_queue(q);
		blk_mq_freeze_queue_wait(q);
		}

block/blk.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -330,4 +330,6 @@ static inline void blk_queue_bounce(struct request_queue q, struct bio *bio)
		}
		#endif /* CONFIG_BOUNCE */

		extern void blk_drain_queue(struct request_queue *q);

		#endif /* BLK_INTERNAL_H */

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