[PATCH] block: do not put mq context in blk_mq_alloc_request_hctx

From: Minchan Kim
Date: Thu Mar 30 2017 - 01:21:16 EST


In blk_mq_alloc_request_hctx, blk_mq_sched_get_request doesn't
get sw context so we don't need to put the context with
blk_mq_put_ctx. Unless, we will see preempt counter underflow.

Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Cc: Omar Sandoval <osandov@xxxxxx>
Cc: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---

Maybe, it would be fixed by someone but I have noticed preempt counter
undeflow problem a few weeks ago and still see the problem with
linux-next.

block/blk-mq.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index a4546f060e80..a6f3998dc4ee 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -321,7 +321,6 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw,

rq = blk_mq_sched_get_request(q, NULL, rw, &alloc_data);

- blk_mq_put_ctx(alloc_data.ctx);
blk_queue_exit(q);

if (!rq)
--
2.7.4