[RFC PATCH 2/3] blk-mq: Fix timeout and state order

Keith Busch
2018-05-21T23:11:30Z

The block layer had been setting the state to in-flight prior to updating
the timer. This is the wrong order since the timeout handler could observe
the in-flight state with the older timeout, believing the request had
expired when in fact it is just getting started.

Signed-off-by: Keith Busch <keith.busch@intel.com>
---
block/blk-mq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 8b370ed75605..66e5c768803f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -713,8 +713,8 @@ void blk_mq_start_request(struct request *rq)
preempt_disable();
write_seqcount_begin(&rq->gstate_seq);

- blk_mq_rq_update_state(rq, MQ_RQ_IN_FLIGHT);
blk_add_timer(rq);
+ blk_mq_rq_update_state(rq, MQ_RQ_IN_FLIGHT);

write_seqcount_end(&rq->gstate_seq);
preempt_enable();
--
2.14.3