Commit cf02d7d4 authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

blk-mq: factor out a helper blk_mq_limit_depth() 



There are no functional changes, just make code cleaner.

Signed-off-by: default avatarYu Kuai <yukuai@fnnas.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1db61b0a

block/blk-mq.c

+37 −25
Original line number Diff line number Diff line
@@ -498,25 +498,16 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data) 
	return rq_list_pop(data->cached_rqs);

}



static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)

static void blk_mq_limit_depth(struct blk_mq_alloc_data *data)

{

	struct request_queue *q = data->q;

	u64 alloc_time_ns = 0;

	struct request *rq;

	unsigned int tag;



	/* alloc_time includes depth and tag waits */

	if (blk_queue_rq_alloc_time(q))

		alloc_time_ns = blk_time_get_ns();



	if (data->cmd_flags & REQ_NOWAIT)

		data->flags |= BLK_MQ_REQ_NOWAIT;

	struct elevator_mq_ops *ops;



retry:

	data->ctx = blk_mq_get_ctx(q);

	data->hctx = blk_mq_map_queue(data->cmd_flags, data->ctx);

	/* If no I/O scheduler has been configured, don't limit requests */

	if (!data->q->elevator) {

		blk_mq_tag_busy(data->hctx);

		return;

	}



	if (q->elevator) {

	/*

	 * All requests use scheduler tags when an I/O scheduler is

	 * enabled for the queue.
@@ -525,22 +516,43 @@ static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data) 


	/*

	 * Flush/passthrough requests are special and go directly to the

		 * dispatch list.

	 * dispatch list, they are not subject to the async_depth limit.

	 */

		if ((data->cmd_flags & REQ_OP_MASK) != REQ_OP_FLUSH &&

		    !blk_op_is_passthrough(data->cmd_flags)) {

			struct elevator_mq_ops *ops = &q->elevator->type->ops;

	if ((data->cmd_flags & REQ_OP_MASK) == REQ_OP_FLUSH ||

	    blk_op_is_passthrough(data->cmd_flags))

		return;



	WARN_ON_ONCE(data->flags & BLK_MQ_REQ_RESERVED);



	data->rq_flags |= RQF_USE_SCHED;



	/*

	 * By default, sync requests have no limit, and async requests are

	 * limited to async_depth.

	 */

	ops = &data->q->elevator->type->ops;

	if (ops->limit_depth)

		ops->limit_depth(data->cmd_flags, data);

}

	} else {

		blk_mq_tag_busy(data->hctx);

	}



static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)

{

	struct request_queue *q = data->q;

	u64 alloc_time_ns = 0;

	struct request *rq;

	unsigned int tag;



	/* alloc_time includes depth and tag waits */

	if (blk_queue_rq_alloc_time(q))

		alloc_time_ns = blk_time_get_ns();



	if (data->cmd_flags & REQ_NOWAIT)

		data->flags |= BLK_MQ_REQ_NOWAIT;



retry:

	data->ctx = blk_mq_get_ctx(q);

	data->hctx = blk_mq_map_queue(data->cmd_flags, data->ctx);



	blk_mq_limit_depth(data);

	if (data->flags & BLK_MQ_REQ_RESERVED)

		data->rq_flags |= RQF_RESV;