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 <hch@xxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
block/blk-mq-sched.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index 4be652fa38e7..ba21449439cc 100644
--- 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;
}
--
2.31.1
