Commit 807592a4 authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

block: Let blk_drain_queue() caller obtain the queue lock 



Let the caller of blk_drain_queue() obtain the queue lock to improve
readability of the patch called "Avoid that request_fn is invoked on
a dead queue".

Signed-off-by: default avatarBart Van Assche <bvanassche@acm.org>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Chanho Min <chanho.min@lge.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3f3299d5

block/blk-core.c

+18 −12
Original line number Diff line number Diff line
@@ -349,7 +349,7 @@ void blk_put_queue(struct request_queue *q) 
EXPORT_SYMBOL(blk_put_queue);



/**

 * blk_drain_queue - drain requests from request_queue

 * __blk_drain_queue - drain requests from request_queue

 * @q: queue to drain

 * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV

 *
@@ -357,15 +357,17 @@ EXPORT_SYMBOL(blk_put_queue); 
 * If not, only ELVPRIV requests are drained.  The caller is responsible

 * for ensuring that no new requests which need to be drained are queued.

 */

void blk_drain_queue(struct request_queue *q, bool drain_all)

static void __blk_drain_queue(struct request_queue *q, bool drain_all)

	__releases(q->queue_lock)

	__acquires(q->queue_lock)

{

	int i;



	lockdep_assert_held(q->queue_lock);



	while (true) {

		bool drain = false;



		spin_lock_irq(q->queue_lock);



		/*

		 * The caller might be trying to drain @q before its

		 * elevator is initialized.
@@ -401,11 +403,14 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) 
			}

		}



		spin_unlock_irq(q->queue_lock);



		if (!drain)

			break;



		spin_unlock_irq(q->queue_lock);



		msleep(10);



		spin_lock_irq(q->queue_lock);

	}



	/*
@@ -416,13 +421,9 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) 
	if (q->request_fn) {

		struct request_list *rl;



		spin_lock_irq(q->queue_lock);



		blk_queue_for_each_rl(rl, q)

			for (i = 0; i < ARRAY_SIZE(rl->wait); i++)

				wake_up_all(&rl->wait[i]);



		spin_unlock_irq(q->queue_lock);

	}

}
@@ -446,7 +447,10 @@ void blk_queue_bypass_start(struct request_queue *q) 
	spin_unlock_irq(q->queue_lock);



	if (drain) {

		blk_drain_queue(q, false);

		spin_lock_irq(q->queue_lock);

		__blk_drain_queue(q, false);

		spin_unlock_irq(q->queue_lock);



		/* ensure blk_queue_bypass() is %true inside RCU read lock */

		synchronize_rcu();

	}
@@ -504,7 +508,9 @@ void blk_cleanup_queue(struct request_queue *q) 
	mutex_unlock(&q->sysfs_lock);



	/* drain all requests queued before DYING marking */

	blk_drain_queue(q, true);

	spin_lock_irq(lock);

	__blk_drain_queue(q, true);

	spin_unlock_irq(lock);



	/* @q won't process any more request, flush async actions */

	del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);

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