From 0f95549c0ea1e8075ae049202088b2c6a0cb40ad Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Wed, 17 Jan 2018 11:25:56 -0500 Subject: [PATCH] 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: Mike Snitzer Signed-off-by: Jens Axboe --- block/blk-mq.c | 79 +++++++++++++++++++++++++++++++++----------------- 1 file changed, 52 insertions(+), 27 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index ec429be05729..ddc46f215bfa 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1738,9 +1738,9 @@ 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, - struct request *rq, - blk_qc_t *cookie) +static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, + struct request *rq, + blk_qc_t *cookie) { struct request_queue *q = rq->q; struct blk_mq_queue_data bd = { @@ -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); }