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Commit caf8eb0d authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq-sched: move actual dispatching into one helper 



So that it becomes easy to support to dispatch from sw queue in the
following patch.

No functional change.

Reviewed-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: default avatarOmar Sandoval <osandov@fb.com>
Suggested-by: Christoph Hellwig <hch@lst.de> # for simplifying dispatch logic
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 5e3d02bb

block/blk-mq-sched.c

+24 −19
Original line number Original line Diff line number Diff line
@@ -89,12 +89,26 @@ static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx) 
	return false;

	return false;

}

}





static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)

{

	struct request_queue *q = hctx->queue;

	struct elevator_queue *e = q->elevator;

	LIST_HEAD(rq_list);



	do {

		struct request *rq = e->type->ops.mq.dispatch_request(hctx);



		if (!rq)

			break;

		list_add(&rq->queuelist, &rq_list);

	} while (blk_mq_dispatch_rq_list(q, &rq_list));

}



void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)

void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)

{

{

	struct request_queue *q = hctx->queue;

	struct request_queue *q = hctx->queue;

	struct elevator_queue *e = q->elevator;

	struct elevator_queue *e = q->elevator;

	const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;

	const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;

	bool do_sched_dispatch = true;

	LIST_HEAD(rq_list);

	LIST_HEAD(rq_list);





	/* RCU or SRCU read lock is needed before checking quiesced flag */

	/* RCU or SRCU read lock is needed before checking quiesced flag */
@@ -122,30 +136,21 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) 
	 * scheduler, we can no longer merge or sort them. So it's best to

	 * scheduler, we can no longer merge or sort them. So it's best to

	 * leave them there for as long as we can. Mark the hw queue as

	 * leave them there for as long as we can. Mark the hw queue as

	 * needing a restart in that case.

	 * needing a restart in that case.

	 *

	 * We want to dispatch from the scheduler if there was nothing

	 * on the dispatch list or we were able to dispatch from the

	 * dispatch list.

	 */

	 */

	if (!list_empty(&rq_list)) {

	if (!list_empty(&rq_list)) {

		blk_mq_sched_mark_restart_hctx(hctx);

		blk_mq_sched_mark_restart_hctx(hctx);

		do_sched_dispatch = blk_mq_dispatch_rq_list(q, &rq_list);

		if (blk_mq_dispatch_rq_list(q, &rq_list) && has_sched_dispatch)

	} else if (!has_sched_dispatch) {

			blk_mq_do_dispatch_sched(hctx);

	} else if (has_sched_dispatch) {

		blk_mq_do_dispatch_sched(hctx);

	} else {

		blk_mq_flush_busy_ctxs(hctx, &rq_list);

		blk_mq_flush_busy_ctxs(hctx, &rq_list);

		blk_mq_dispatch_rq_list(q, &rq_list);

		blk_mq_dispatch_rq_list(q, &rq_list);

	}

	}



	/*

	 * We want to dispatch from the scheduler if there was nothing

	 * on the dispatch list or we were able to dispatch from the

	 * dispatch list.

	 */

	if (do_sched_dispatch && has_sched_dispatch) {

		do {

			struct request *rq;



			rq = e->type->ops.mq.dispatch_request(hctx);

			if (!rq)

				break;

			list_add(&rq->queuelist, &rq_list);

		} while (blk_mq_dispatch_rq_list(q, &rq_list));

	}

}

}





bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,

bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,