Commit 71539717 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: split request allocation components into helpers 



This is in preparation for a fix, but serves as a cleanup as well moving
the cached vs regular alloc logic out of blk_mq_submit_bio().

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent c5fc7b93

block/blk-mq.c

+48 −23
Original line number Diff line number Diff line
@@ -2478,6 +2478,51 @@ static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug) 
	return BLK_MAX_REQUEST_COUNT;

}



static struct request *blk_mq_get_new_requests(struct request_queue *q,

					       struct blk_plug *plug,

					       struct bio *bio)

{

	struct blk_mq_alloc_data data = {

		.q		= q,

		.nr_tags	= 1,

		.cmd_flags	= bio->bi_opf,

	};

	struct request *rq;



	if (plug) {

		data.nr_tags = plug->nr_ios;

		plug->nr_ios = 1;

		data.cached_rq = &plug->cached_rq;

	}



	rq = __blk_mq_alloc_requests(&data);

	if (rq)

		return rq;



	rq_qos_cleanup(q, bio);

	if (bio->bi_opf & REQ_NOWAIT)

		bio_wouldblock_error(bio);

	return NULL;

}



static inline struct request *blk_mq_get_request(struct request_queue *q,

						 struct blk_plug *plug,

						 struct bio *bio)

{

	if (plug) {

		struct request *rq;



		rq = rq_list_peek(&plug->cached_rq);

		if (rq) {

			plug->cached_rq = rq_list_next(rq);

			INIT_LIST_HEAD(&rq->queuelist);

			return rq;

		}

	}



	return blk_mq_get_new_requests(q, plug, bio);

}



/**

 * blk_mq_submit_bio - Create and send a request to block device.

 * @bio: Bio pointer.
@@ -2518,29 +2563,9 @@ void blk_mq_submit_bio(struct bio *bio) 
	rq_qos_throttle(q, bio);



	plug = blk_mq_plug(q, bio);

	if (plug && plug->cached_rq) {

		rq = rq_list_pop(&plug->cached_rq);

		INIT_LIST_HEAD(&rq->queuelist);

	} else {

		struct blk_mq_alloc_data data = {

			.q		= q,

			.nr_tags	= 1,

			.cmd_flags	= bio->bi_opf,

		};



		if (plug) {

			data.nr_tags = plug->nr_ios;

			plug->nr_ios = 1;

			data.cached_rq = &plug->cached_rq;

		}

		rq = __blk_mq_alloc_requests(&data);

		if (unlikely(!rq)) {

			rq_qos_cleanup(q, bio);

			if (bio->bi_opf & REQ_NOWAIT)

				bio_wouldblock_error(bio);

	rq = blk_mq_get_request(q, plug, bio);

	if (unlikely(!rq))

		goto queue_exit;

		}

	}



	trace_block_getrq(bio);