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Commit f3bc78d2 authored by Damien Le Moal's avatar Damien Le Moal Committed by Jens Axboe
Browse files

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: 5700f691 ("mq-deadline: Introduce zone locking support")
Cc: Hannes Reinecke <hare@suse.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
[ bvanassche: edited patch description ]
Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 468f0987

block/mq-deadline.c

+13 −3
Original line number Original line Diff line number Diff line
@@ -535,13 +535,22 @@ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx, 
	spin_unlock(&dd->lock);

	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

 * For zoned block devices, write unlock the target zone of

 * completed write requests. Do this while holding the zone lock

 * completed write requests. Do this while holding the zone lock

 * spinlock so that the zone is never unlocked while deadline_fifo_request()

 * 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;

	struct request_queue *q = rq->q;
@@ -756,7 +765,8 @@ static struct elevator_type mq_deadline = { 
	.ops.mq = {

	.ops.mq = {

		.insert_requests	= dd_insert_requests,

		.insert_requests	= dd_insert_requests,

		.dispatch_request	= dd_dispatch_request,

		.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,

		.next_request		= elv_rb_latter_request,

		.former_request		= elv_rb_former_request,

		.former_request		= elv_rb_former_request,

		.bio_merge		= dd_bio_merge,

		.bio_merge		= dd_bio_merge,