blk-mq: move lockdep_assert_held() into elevator_exit

Commit c48dac1 ("block: don't hold q->sysfs_lock in elevator_init_mq") removes q->sysfs_lock from elevator_init_mq(), but forgot to deal with lockdep_assert_held() called in blk_mq_sched_free_requests() which is run in failure path of elevator_init_mq(). blk_mq_sched_free_requests() is called in the following 3 functions: elevator_init_mq() elevator_exit() blk_cleanup_queue() In blk_cleanup_queue(), blk_mq_sched_free_requests() is followed exactly by 'mutex_lock(&q->sysfs_lock)'. So moving the lockdep_assert_held() from blk_mq_sched_free_requests() into elevator_exit() for fixing the report by syzbot. Reported-by: [email protected] Fixed: c48dac1 ("block: don't hold q->sysfs_lock in elevator_init_mq") Reviewed-by: Bart Van Assche <[email protected]> Reviewed-by: Damien Le Moal <[email protected]> Signed-off-by: Ming Lei <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
berg · Sep 26, 2019 · 284b94b · 284b94b
1 parent f41def3
commit 284b94b
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
@@ -555,8 +555,6 @@ void blk_mq_sched_free_requests(struct request_queue *q)
 	struct blk_mq_hw_ctx *hctx;
 	int i;
 
-	lockdep_assert_held(&q->sysfs_lock);
-
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (hctx->sched_tags)
 			blk_mq_free_rqs(q->tag_set, hctx->sched_tags, i);

diff --git a/block/blk.h b/block/blk.h
@@ -194,6 +194,8 @@ void elv_unregister_queue(struct request_queue *q);
 static inline void elevator_exit(struct request_queue *q,
 		struct elevator_queue *e)
 {
+	lockdep_assert_held(&q->sysfs_lock);
+
 	blk_mq_sched_free_requests(q);
 	__elevator_exit(q, e);
 }