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Commit 0f95549c authored by Mike Snitzer's avatar Mike Snitzer Committed by Jens Axboe
Browse files

blk-mq: factor out a few helpers from __blk_mq_try_issue_directly 



No functional change.  Just makes code flow more logically.

In following commit, __blk_mq_try_issue_directly() will be used to
return the dispatch result (blk_status_t) to DM.  DM needs this
information to improve IO merging.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7df938fb

block/blk-mq.c

+52 −27
Original line number Diff line number Diff line
@@ -1738,7 +1738,7 @@ static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq) 
	return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);

}



static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,

static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,

					    struct request *rq,

					    blk_qc_t *cookie)

{
@@ -1749,6 +1749,43 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, 
	};

	blk_qc_t new_cookie;

	blk_status_t ret;



	new_cookie = request_to_qc_t(hctx, rq);



	/*

	 * For OK queue, we are done. For error, caller may kill it.

	 * Any other error (busy), just add it to our list as we

	 * previously would have done.

	 */

	ret = q->mq_ops->queue_rq(hctx, &bd);

	switch (ret) {

	case BLK_STS_OK:

		*cookie = new_cookie;

		break;

	case BLK_STS_RESOURCE:

		__blk_mq_requeue_request(rq);

		break;

	default:

		*cookie = BLK_QC_T_NONE;

		break;

	}



	return ret;

}



static void __blk_mq_fallback_to_insert(struct blk_mq_hw_ctx *hctx,

					struct request *rq,

					bool run_queue)

{

	blk_mq_sched_insert_request(rq, false, run_queue, false,

					hctx->flags & BLK_MQ_F_BLOCKING);

}



static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,

						struct request *rq,

						blk_qc_t *cookie)

{

	struct request_queue *q = rq->q;

	bool run_queue = true;



	/* RCU or SRCU read lock is needed before checking quiesced flag */
@@ -1768,41 +1805,29 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, 
		goto insert;

	}



	new_cookie = request_to_qc_t(hctx, rq);



	/*

	 * For OK queue, we are done. For error, kill it. Any other

	 * error (busy), just add it to our list as we previously

	 * would have done

	 */

	ret = q->mq_ops->queue_rq(hctx, &bd);

	switch (ret) {

	case BLK_STS_OK:

		*cookie = new_cookie;

		return;

	case BLK_STS_RESOURCE:

		__blk_mq_requeue_request(rq);

		goto insert;

	default:

		*cookie = BLK_QC_T_NONE;

		blk_mq_end_request(rq, ret);

		return;

	}



	return __blk_mq_issue_directly(hctx, rq, cookie);

insert:

	blk_mq_sched_insert_request(rq, false, run_queue, false,

					hctx->flags & BLK_MQ_F_BLOCKING);

	__blk_mq_fallback_to_insert(hctx, rq, run_queue);



	return BLK_STS_OK;

}



static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,

		struct request *rq, blk_qc_t *cookie)

{

	blk_status_t ret;

	int srcu_idx;



	might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING);



	hctx_lock(hctx, &srcu_idx);

	__blk_mq_try_issue_directly(hctx, rq, cookie);



	ret = __blk_mq_try_issue_directly(hctx, rq, cookie);

	if (ret == BLK_STS_RESOURCE)

		__blk_mq_fallback_to_insert(hctx, rq, true);

	else if (ret != BLK_STS_OK)

		blk_mq_end_request(rq, ret);



	hctx_unlock(hctx, srcu_idx);

}