Merge tag 'for-linus-2019-09-27' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "A few fixes/changes to round off this merge window. This contains:

   - Small series making some functional tweaks to blk-iocost (Tejun)

   - Elevator switch locking fix (Ming)

   - Kill redundant call in blk-wbt (Yufen)

   - Fix flush timeout handling (Yufen)"

* tag 'for-linus-2019-09-27' of git://git.kernel.dk/linux-block:
  block: fix null pointer dereference in blk_mq_rq_timed_out()
  rq-qos: get rid of redundant wbt_update_limits()
  iocost: bump up default latency targets for hard disks
  iocost: improve nr_lagging handling
  iocost: better trace vrate changes
  block: don't release queue's sysfs lock during switching elevator
  blk-mq: move lockdep_assert_held() into elevator_exit

1 files changed, 4 insertions, 1 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 29275f5a996f..6e3b15f70cd7 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -918,7 +918,10 @@ static bool blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
 	 */
 	if (blk_mq_req_expired(rq, next))
 		blk_mq_rq_timed_out(rq, reserved);
-	if (refcount_dec_and_test(&rq->ref))
+
+	if (is_flush_rq(rq, hctx))
+		rq->end_io(rq, 0);
+	else if (refcount_dec_and_test(&rq->ref))
 		__blk_mq_free_request(rq);
 
 	return true;