[PATCH 4/4] block: track queue dying state automatically for modeling queue freeze lockdep

[Ming Lei <ming.lei@xxxxxxxxxx>]

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

Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
 block/blk-mq.c         |  5 +++--
 block/blk.h            | 12 ++++++------
 block/genhd.c          |  7 +++----
 include/linux/blkdev.h |  6 +++++-
 4 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 32b398d0c598..1f9c943175ef 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -133,6 +133,7 @@ static bool blk_freeze_set_owner(struct request_queue *q,
 		q->mq_freeze_disk_dead = !q->disk ||
 			test_bit(GD_DEAD, &q->disk->state) ||
 			!blk_queue_registered(q);
+		q->mq_freeze_queue_dying = blk_queue_dying(q);
 		return true;
 	}
 
@@ -189,7 +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);
+		blk_freeze_acquire_lock(q);
 }
 EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
 
@@ -237,7 +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);
+		blk_unfreeze_release_lock(q);
 }
 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
 
diff --git a/block/blk.h b/block/blk.h
index 8708168d50e4..cbf6a676ffe9 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -721,26 +721,26 @@ void blk_integrity_prepare(struct request *rq);
 void blk_integrity_complete(struct request *rq, unsigned int nr_bytes);
 
 #ifdef CONFIG_LOCKDEP
-static inline void blk_freeze_acquire_lock(struct request_queue *q, bool queue_dying)
+static inline void blk_freeze_acquire_lock(struct request_queue *q)
 {
 	if (!q->mq_freeze_disk_dead)
 		rwsem_acquire(&q->io_lockdep_map, 0, 1, _RET_IP_);
-	if (!queue_dying)
+	if (!q->mq_freeze_queue_dying)
 		rwsem_acquire(&q->q_lockdep_map, 0, 1, _RET_IP_);
 }
 
-static inline void blk_unfreeze_release_lock(struct request_queue *q, bool queue_dying)
+static inline void blk_unfreeze_release_lock(struct request_queue *q)
 {
-	if (!queue_dying)
+	if (!q->mq_freeze_queue_dying)
 		rwsem_release(&q->q_lockdep_map, _RET_IP_);
 	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_freeze_acquire_lock(struct request_queue *q)
 {
 }
-static inline void blk_unfreeze_release_lock(struct request_queue *q, bool queue_dying)
+static inline void blk_unfreeze_release_lock(struct request_queue *q)
 {
 }
 #endif
diff --git a/block/genhd.c b/block/genhd.c
index fa4183cfb436..be65aa158bad 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -661,7 +661,7 @@ void del_gendisk(struct gendisk *disk)
 	struct request_queue *q = disk->queue;
 	struct block_device *part;
 	unsigned long idx;
-	bool start_drain, queue_dying;
+	bool start_drain;
 
 	might_sleep();
 
@@ -690,9 +690,8 @@ void del_gendisk(struct gendisk *disk)
 	 */
 	mutex_lock(&disk->open_mutex);
 	start_drain = __blk_mark_disk_dead(disk);
-	queue_dying = blk_queue_dying(q);
 	if (start_drain)
-		blk_freeze_acquire_lock(q, queue_dying);
+		blk_freeze_acquire_lock(q);
 	xa_for_each_start(&disk->part_tbl, idx, part, 1)
 		drop_partition(part);
 	mutex_unlock(&disk->open_mutex);
@@ -751,7 +750,7 @@ void del_gendisk(struct gendisk *disk)
 	}
 
 	if (start_drain)
-		blk_unfreeze_release_lock(q, queue_dying);
+		blk_unfreeze_release_lock(q);
 }
 EXPORT_SYMBOL(del_gendisk);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 5f7fe8070a53..a698731c1432 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -579,8 +579,12 @@ 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 */
+	/*
+	 * Records disk & queue state in current context, used in unfreeze
+	 * queue
+	 */
 	bool			mq_freeze_disk_dead;
+	bool			mq_freeze_queue_dying;
 #endif
 	wait_queue_head_t	mq_freeze_wq;
 	/*
-- 
2.47.0