path: root/block/mq-deadline.c
diff options
authorDamien Le Moal <>2018-02-28 09:35:29 -0800
committerJens Axboe <>2018-03-01 08:39:24 -0700
commitf3bc78d2d4b489590540ab2788d5376583e28173 (patch)
tree0a6dd46bd1feef14581a7fd0ddc7d704a54c4952 /block/mq-deadline.c
parent468f098734ab095b72d8af26bcd4bcb2ed31a3be (diff)
mq-deadline: Make sure to always unlock zones
In case of a failed write request (all retries failed) and when using libata, the SCSI error handler calls scsi_finish_command(). In the case of blk-mq this means that scsi_mq_done() does not get called, that blk_mq_complete_request() does not get called and also that the mq-deadline .completed_request() method is not called. This results in the target zone of the failed write request being left in a locked state, preventing that any new write requests are issued to the same zone. Fix this by replacing the .completed_request() method with the .finish_request() method as this method is always called whether or not a request completes successfully. Since the .finish_request() method is only called by the blk-mq core if a .prepare_request() method exists, add a dummy .prepare_request() method. Fixes: 5700f69178e9 ("mq-deadline: Introduce zone locking support") Cc: Hannes Reinecke <> Reviewed-by: Ming Lei <> Signed-off-by: Damien Le Moal <> [ bvanassche: edited patch description ] Signed-off-by: Bart Van Assche <> Signed-off-by: Jens Axboe <>
Diffstat (limited to 'block/mq-deadline.c')
1 files changed, 13 insertions, 3 deletions
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index c56f211c8440..8ec0ba9f5386 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -536,12 +536,21 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx,
+ * Nothing to do here. This is defined only to ensure that .finish_request
+ * method is called upon request completion.
+ */
+static void dd_prepare_request(struct request *rq, struct bio *bio)
* For zoned block devices, write unlock the target zone of
* completed write requests. Do this while holding the zone lock
* spinlock so that the zone is never unlocked while deadline_fifo_request()
- * while deadline_next_request() are executing.
+ * or deadline_next_request() are executing. This function is called for
+ * all requests, whether or not these requests complete successfully.
-static void dd_completed_request(struct request *rq)
+static void dd_finish_request(struct request *rq)
struct request_queue *q = rq->q;
@@ -756,7 +765,8 @@ static struct elevator_type mq_deadline = { = {
.insert_requests = dd_insert_requests,
.dispatch_request = dd_dispatch_request,
- .completed_request = dd_completed_request,
+ .prepare_request = dd_prepare_request,
+ .finish_request = dd_finish_request,
.next_request = elv_rb_latter_request,
.former_request = elv_rb_former_request,
.bio_merge = dd_bio_merge,