blk-mq: allow setting of per-request timeouts

Currently blk-mq uses the queue timeout for all requests. But
for some commands, drivers may want to set a specific timeout
for special requests. Allow this to be passed in through
request->timeout, and use it if set.

Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 6 insertions, 2 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 54e78863c083..9bc075335d06 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -454,9 +454,13 @@ static void blk_mq_start_request(struct request *rq, bool last)
         /*
          * Just mark start time and set the started bit. Due to memory
          * ordering, we know we'll see the correct deadline as long as
-         * REQ_ATOMIC_STARTED is seen.
+         * REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
+         * unless one has been set in the request.
          */
-        rq->deadline = jiffies + q->rq_timeout;
+        if (!rq->timeout)
+                rq->deadline = jiffies + q->rq_timeout;
+        else
+                rq->deadline = jiffies + rq->timeout;
 
         /*
          * Mark us as started and clear complete. Complete might have been