2014-01-03 11:29:25

by Ming Lei

Subject: [PATCH] block: blk-mq: fix initializing request's start time

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.

Cc: Jens Axboe <[email protected]>
Signed-off-by: Ming Lei <[email protected]>
---
block/blk-mq.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0974a26..68734f87 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -188,6 +188,8 @@ 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)]++;
}

--
1.7.9.5

2014-01-03 17:04:14

by Jens Axboe

Subject: Re: [PATCH] block: blk-mq: fix initializing request's start time

On 01/03/2014 04:29 AM, Ming Lei wrote:
> 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.

Thanks, applied!

--
Jens Axboe