Commit 34c9f547 authored by Kemeng Shi's avatar Kemeng Shi Committed by Jens Axboe
Browse files

blk-mq: make blk_mq_commit_rqs a general function for all commits 



1. move blk_mq_commit_rqs forward before functions need commits.
2. add queued check and only commits request if any request was queued
in blk_mq_commit_rqs to keep commit behavior consistent and remove
unnecessary commit.
3. split the queued clearing from blk_mq_plug_commit_rqs as it is
not wanted general.
4. sync current caller of blk_mq_commit_rqs with new general
blk_mq_commit_rqs.
5. document rule for unusual cases which need explicit commit_rqs.

Suggested-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 3e368fb0

block/blk-mq.c

+23 −14
Original line number Diff line number Diff line
@@ -2007,6 +2007,23 @@ static void blk_mq_release_budgets(struct request_queue *q, 
	}

}



/*

 * blk_mq_commit_rqs will notify driver using bd->last that there is no

 * more requests. (See comment in struct blk_mq_ops for commit_rqs for

 * details)

 * Attention, we should explicitly call this in unusual cases:

 *  1) did not queue everything initially scheduled to queue

 *  2) the last attempt to queue a request failed

 */

static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued,

			      bool from_schedule)

{

	if (hctx->queue->mq_ops->commit_rqs && queued) {

		trace_block_unplug(hctx->queue, queued, !from_schedule);

		hctx->queue->mq_ops->commit_rqs(hctx);

	}

}



/*

 * Returns true if we did some work AND can potentially do more.

 */
@@ -2555,16 +2572,6 @@ void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx, 
	spin_unlock(&ctx->lock);

}



static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int *queued,

			      bool from_schedule)

{

	if (hctx->queue->mq_ops->commit_rqs) {

		trace_block_unplug(hctx->queue, *queued, !from_schedule);

		hctx->queue->mq_ops->commit_rqs(hctx);

	}

	*queued = 0;

}



static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,

		unsigned int nr_segs)

{
@@ -2700,8 +2707,10 @@ static void blk_mq_plug_issue_direct(struct blk_plug *plug) 
		blk_status_t ret;



		if (hctx != rq->mq_hctx) {

			if (hctx)

				blk_mq_commit_rqs(hctx, &queued, false);

			if (hctx) {

				blk_mq_commit_rqs(hctx, queued, false);

				queued = 0;

			}

			hctx = rq->mq_hctx;

		}
@@ -2713,7 +2722,7 @@ static void blk_mq_plug_issue_direct(struct blk_plug *plug) 
		case BLK_STS_RESOURCE:

		case BLK_STS_DEV_RESOURCE:

			blk_mq_request_bypass_insert(rq, false, true);

			blk_mq_commit_rqs(hctx, &queued, false);

			blk_mq_commit_rqs(hctx, queued, false);

			return;

		default:

			blk_mq_end_request(rq, ret);
@@ -2727,7 +2736,7 @@ static void blk_mq_plug_issue_direct(struct blk_plug *plug) 
	 * there was more coming, but that turned out to be a lie.

	 */

	if (errors)

		blk_mq_commit_rqs(hctx, &queued, false);

		blk_mq_commit_rqs(hctx, queued, false);

}



static void __blk_mq_flush_plug_list(struct request_queue *q,