From f3bc78d2d4b489590540ab2788d5376583e28173 Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Wed, 28 Feb 2018 09:35:29 -0800 Subject: [PATCH] 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 --- block/mq-deadline.c | 16 +++++++++++++--- 1 file 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 @@ -535,13 +535,22 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx, spin_unlock(&dd->lock); } +/* + * 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 = { .ops.mq = { .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,