[PATCH 3.13 048/187] blk-mq: fix initializing request's start time

Kamal Mostafa
2014-09-15T22:23:58Z

From: Ming Lei <tom.leiming@gmail.com>

commit 0fec08b4ecfc36fd8a64432343b2964fb86d2675 upstream.

blk_rq_init() is called in req's complete handler to initialize
the request, so the members of start_time and start_time_ns might
become inaccurate when it is allocated in future.

The patch initializes the two members in blk_mq_rq_ctx_init() to
fix the problem.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
block/blk-mq.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7f9b1f6..2192cf4 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -179,6 +179,8 @@ static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,

rq->mq_ctx = ctx;
rq->cmd_flags = rw_flags;
+ rq->start_time = jiffies;
+ set_start_time_ns(rq);
ctx->rq_dispatched[rw_is_sync(rw_flags)]++;
}

--
1.9.1