Commit 87c037d1 authored by Jens Axboe's avatar Jens Axboe
Browse files

block: return whether or not to unplug through boolean 



Instead of returning the same queue request through a request pointer,
use a boolean to accomplish the same.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 8a7d267b

block/blk-merge.c

+5 −6
Original line number Diff line number Diff line
@@ -1067,9 +1067,8 @@ static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q, 
 * @q: request_queue new bio is being queued at

 * @bio: new bio being queued

 * @nr_segs: number of segments in @bio

 * @same_queue_rq: pointer to &struct request that gets filled in when

 * another request associated with @q is found on the plug list

 * (optional, may be %NULL)

 * @same_queue_rq: output value, will be true if there's an existing request

 * from the passed in @q already in the plug list

 *

 * Determine whether @bio being queued on @q can be merged with the previous

 * request on %current's plugged list.  Returns %true if merge was successful,
@@ -1085,7 +1084,7 @@ static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q, 
 * Caller must ensure !blk_queue_nomerges(q) beforehand.

 */

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

		unsigned int nr_segs, struct request **same_queue_rq)

		unsigned int nr_segs, bool *same_queue_rq)

{

	struct blk_plug *plug;

	struct request *rq;
@@ -1096,12 +1095,12 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, 


	/* check the previously added entry for a quick merge attempt */

	rq = list_last_entry(&plug->mq_list, struct request, queuelist);

	if (rq->q == q && same_queue_rq) {

	if (rq->q == q) {

		/*

		 * Only blk-mq multiple hardware queues case checks the rq in

		 * the same queue, there should be only one such rq in a queue

		 */

		*same_queue_rq = rq;

		*same_queue_rq = true;

	}

	if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) == BIO_MERGE_OK)

		return true;

block/blk-mq.c

+9 −7
Original line number Diff line number Diff line
@@ -2432,7 +2432,7 @@ void blk_mq_submit_bio(struct bio *bio) 
	const int is_flush_fua = op_is_flush(bio->bi_opf);

	struct request *rq;

	struct blk_plug *plug;

	struct request *same_queue_rq = NULL;

	bool same_queue_rq = false;

	unsigned int nr_segs = 1;

	blk_status_t ret;
@@ -2525,6 +2525,8 @@ void blk_mq_submit_bio(struct bio *bio) 
		/* Insert the request at the IO scheduler queue */

		blk_mq_sched_insert_request(rq, false, true, true);

	} else if (plug && !blk_queue_nomerges(q)) {

		struct request *next_rq = NULL;



		/*

		 * We do limited plugging. If the bio can be merged, do that.

		 * Otherwise the existing request in the plug list will be
@@ -2532,19 +2534,19 @@ void blk_mq_submit_bio(struct bio *bio) 
		 * The plug list might get flushed before this. If that happens,

		 * the plug list is empty, and same_queue_rq is invalid.

		 */

		if (list_empty(&plug->mq_list))

			same_queue_rq = NULL;

		if (same_queue_rq) {

			list_del_init(&same_queue_rq->queuelist);

			next_rq = list_last_entry(&plug->mq_list,

							struct request,

							queuelist);

			list_del_init(&next_rq->queuelist);

			plug->rq_count--;

		}

		blk_add_rq_to_plug(plug, rq);

		trace_block_plug(q);



		if (same_queue_rq) {

		if (next_rq) {

			trace_block_unplug(q, 1, true);

			blk_mq_try_issue_directly(same_queue_rq->mq_hctx,

						  same_queue_rq);

			blk_mq_try_issue_directly(next_rq->mq_hctx, next_rq);

		}

	} else if ((q->nr_hw_queues > 1 && is_sync) ||

		   !rq->mq_hctx->dispatch_busy) {

block/blk.h

+1 −1
Original line number Diff line number Diff line
@@ -218,7 +218,7 @@ void blk_add_timer(struct request *req); 
void blk_print_req_error(struct request *req, blk_status_t status);



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

		unsigned int nr_segs, struct request **same_queue_rq);

		unsigned int nr_segs, bool *same_queue_rq);

bool blk_bio_list_merge(struct request_queue *q, struct list_head *list,

			struct bio *bio, unsigned int nr_segs);