blk-mq: don't grab ->q_usage_counter in blk_mq_sched_bio_merge

blk_mq_sched_bio_merge is only called from blk-mq.c:blk_attempt_bio_merge(), which is called when queue usage counter is grabbed already: 1) blk_mq_get_new_requests() 2) blk_mq_get_request() - cached request in current plug owns one queue usage counter So don't grab ->q_usage_counter in blk_mq_sched_bio_merge(), and more importantly this nest way causes hang in blk_mq_freeze_queue_wait(). Cc: Christoph Hellwig <[email protected]> Signed-off-by: Ming Lei <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jens Axboe <[email protected]>
valschneider · Nov 11, 2021 · 10f7335 · 10f7335
1 parent 438cd74
commit 10f7335
Showing 1 changed file with 0 additions and 4 deletions.
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
@@ -370,9 +370,6 @@ bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
 	bool ret = false;
 	enum hctx_type type;
 
-	if (bio_queue_enter(bio))
-		return false;
-
 	if (e && e->type->ops.bio_merge) {
 		ret = e->type->ops.bio_merge(q, bio, nr_segs);
 		goto out_put;
@@ -397,7 +394,6 @@ bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio,
 
 	spin_unlock(&ctx->lock);
 out_put:
-	blk_queue_exit(q);
 	return ret;
 }