blk-mq: End unstarted requests on a dying queue

Requests that haven't been started prior to a queue dying can be ended
in error without waiting for them to start and time out.

Signed-off-by: Keith Busch <keith.busch@intel.com>

Added code comment to explain why this is done.

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

1 files changed, 10 insertions, 1 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 78324a2f0e10..2f95747c287e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -625,8 +625,17 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
 {
         struct blk_mq_timeout_data *data = priv;
 
-        if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
+        if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) {
+                /*
+                 * If a request wasn't started before the queue was
+                 * marked dying, kill it here or it'll go unnoticed.
+                 */
+                if (unlikely(blk_queue_dying(rq->q))) {
+                        rq->errors = -EIO;
+                        blk_mq_complete_request(rq);
+                }
                 return;
+        }
         if (rq->cmd_flags & REQ_NO_TIMEOUT)
                 return;