Commit 6f491a8d authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

block: track disk DEAD state automatically for modeling queue freeze lockdep 

Now we only verify the outmost freeze & unfreeze in current context in case
that !q->mq_freeze_depth, so it is reliable to save disk DEAD state when
we want to lock the freeze queue since the state is one per-task variable
now.

Doing this way can kill lots of false positive when freeze queue is
called before adding disk[1].

[1] https://lore.kernel.org/linux-block/6741f6b2.050a0220.1cc393.0017.GAE@google.com/



Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20241127135133.3952153-3-ming.lei@redhat.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent aff09dc1

block/blk-mq.c

+5 −2
Original line number Diff line number Diff line
@@ -131,6 +131,9 @@ static bool blk_freeze_set_owner(struct request_queue *q, 
	if (!q->mq_freeze_depth) {

		q->mq_freeze_owner = owner;

		q->mq_freeze_owner_depth = 1;

		q->mq_freeze_disk_dead = !q->disk ||

			test_bit(GD_DEAD, &q->disk->state) ||

			!blk_queue_registered(q);

		return true;

	}
@@ -187,7 +190,7 @@ bool __blk_freeze_queue_start(struct request_queue *q, 
void blk_freeze_queue_start(struct request_queue *q)

{

	if (__blk_freeze_queue_start(q, current))

		blk_freeze_acquire_lock(q, false, false);

		blk_freeze_acquire_lock(q, false);

}

EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
@@ -235,7 +238,7 @@ bool __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic) 
void blk_mq_unfreeze_queue(struct request_queue *q)

{

	if (__blk_mq_unfreeze_queue(q, false))

		blk_unfreeze_release_lock(q, false, false);

		blk_unfreeze_release_lock(q, false);

}

EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);

block/blk.h

+13 −6
Original line number Diff line number Diff line
@@ -720,22 +720,29 @@ void blk_integrity_verify(struct bio *bio); 
void blk_integrity_prepare(struct request *rq);

void blk_integrity_complete(struct request *rq, unsigned int nr_bytes);



static inline void blk_freeze_acquire_lock(struct request_queue *q, bool

		disk_dead, bool queue_dying)

#ifdef CONFIG_LOCKDEP

static inline void blk_freeze_acquire_lock(struct request_queue *q, bool queue_dying)

{

	if (!disk_dead)

	if (!q->mq_freeze_disk_dead)

		rwsem_acquire(&q->io_lockdep_map, 0, 1, _RET_IP_);

	if (!queue_dying)

		rwsem_acquire(&q->q_lockdep_map, 0, 1, _RET_IP_);

}



static inline void blk_unfreeze_release_lock(struct request_queue *q, bool

		disk_dead, bool queue_dying)

static inline void blk_unfreeze_release_lock(struct request_queue *q, bool queue_dying)

{

	if (!queue_dying)

		rwsem_release(&q->q_lockdep_map, _RET_IP_);

	if (!disk_dead)

	if (!q->mq_freeze_disk_dead)

		rwsem_release(&q->io_lockdep_map, _RET_IP_);

}

#else

static inline void blk_freeze_acquire_lock(struct request_queue *q, bool queue_dying)

{

}

static inline void blk_unfreeze_release_lock(struct request_queue *q, bool queue_dying)

{

}

#endif



#endif /* BLK_INTERNAL_H */

block/elevator.c

+2 −2
Original line number Diff line number Diff line
@@ -602,14 +602,14 @@ void elevator_init_mq(struct request_queue *q) 
	 * Disk isn't added yet, so verifying queue lock only manually.

	 */

	blk_freeze_queue_start_non_owner(q);

	blk_freeze_acquire_lock(q, true, false);

	blk_freeze_acquire_lock(q, false);

	blk_mq_freeze_queue_wait(q);



	blk_mq_cancel_work_sync(q);



	err = blk_mq_init_sched(q, e);



	blk_unfreeze_release_lock(q, true, false);

	blk_unfreeze_release_lock(q, false);

	blk_mq_unfreeze_queue_non_owner(q);



	if (err) {

block/genhd.c

+2 −2
Original line number Diff line number Diff line
@@ -692,7 +692,7 @@ void del_gendisk(struct gendisk *disk) 
	start_drain = __blk_mark_disk_dead(disk);

	queue_dying = blk_queue_dying(q);

	if (start_drain)

		blk_freeze_acquire_lock(q, true, queue_dying);

		blk_freeze_acquire_lock(q, queue_dying);

	xa_for_each_start(&disk->part_tbl, idx, part, 1)

		drop_partition(part);

	mutex_unlock(&disk->open_mutex);
@@ -748,7 +748,7 @@ void del_gendisk(struct gendisk *disk) 
		blk_mq_exit_queue(q);



	if (start_drain)

		blk_unfreeze_release_lock(q, true, queue_dying);

		blk_unfreeze_release_lock(q, queue_dying);

}

EXPORT_SYMBOL(del_gendisk);

include/linux/blkdev.h

+2 −0
Original line number Diff line number Diff line
@@ -581,6 +581,8 @@ struct request_queue { 
#ifdef CONFIG_LOCKDEP

	struct task_struct	*mq_freeze_owner;

	int			mq_freeze_owner_depth;

	/* Records disk state in current context, used in unfreeze queue */

	bool			mq_freeze_disk_dead;

#endif

	wait_queue_head_t	mq_freeze_wq;

	/*