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Commit 4ecd4fef authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: use an atomic_t for mq_freeze_depth 



lockdep gets unhappy about the not disabling irqs when using the queue_lock
around it.  Instead of trying to fix that up just switch to an atomic_t
and get rid of the lock.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 5b3f341f

block/blk-mq.c

+10 −14
Original line number Diff line number Diff line
@@ -89,7 +89,8 @@ static int blk_mq_queue_enter(struct request_queue *q, gfp_t gfp) 
			return -EBUSY;



		ret = wait_event_interruptible(q->mq_freeze_wq,

				!q->mq_freeze_depth || blk_queue_dying(q));

				!atomic_read(&q->mq_freeze_depth) ||

				blk_queue_dying(q));

		if (blk_queue_dying(q))

			return -ENODEV;

		if (ret)
@@ -112,13 +113,10 @@ static void blk_mq_usage_counter_release(struct percpu_ref *ref) 


void blk_mq_freeze_queue_start(struct request_queue *q)

{

	bool freeze;

	int freeze_depth;



	spin_lock_irq(q->queue_lock);

	freeze = !q->mq_freeze_depth++;

	spin_unlock_irq(q->queue_lock);



	if (freeze) {

	freeze_depth = atomic_inc_return(&q->mq_freeze_depth);

	if (freeze_depth == 1) {

		percpu_ref_kill(&q->mq_usage_counter);

		blk_mq_run_hw_queues(q, false);

	}
@@ -143,13 +141,11 @@ EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); 


void blk_mq_unfreeze_queue(struct request_queue *q)

{

	bool wake;

	int freeze_depth;



	spin_lock_irq(q->queue_lock);

	wake = !--q->mq_freeze_depth;

	WARN_ON_ONCE(q->mq_freeze_depth < 0);

	spin_unlock_irq(q->queue_lock);

	if (wake) {

	freeze_depth = atomic_dec_return(&q->mq_freeze_depth);

	WARN_ON_ONCE(freeze_depth < 0);

	if (!freeze_depth) {

		percpu_ref_reinit(&q->mq_usage_counter);

		wake_up_all(&q->mq_freeze_wq);

	}
@@ -2081,7 +2077,7 @@ void blk_mq_free_queue(struct request_queue *q) 
/* Basically redo blk_mq_init_queue with queue frozen */

static void blk_mq_queue_reinit(struct request_queue *q)

{

	WARN_ON_ONCE(!q->mq_freeze_depth);

	WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth));



	blk_mq_sysfs_unregister(q);

include/linux/blkdev.h

+1 −1
Original line number Diff line number Diff line
@@ -444,7 +444,7 @@ struct request_queue { 
	struct mutex		sysfs_lock;



	int			bypass_depth;

	int			mq_freeze_depth;

	atomic_t		mq_freeze_depth;



#if defined(CONFIG_BLK_DEV_BSG)

	bsg_job_fn		*bsg_job_fn;