Messages in this thread Patch in this message | | | From | Jianchao Wang <> | Subject | [PATCH V4 2/5] blk-mq: refactor the code of issue request directly | Date | Fri, 2 Nov 2018 15:08:53 +0800 |
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Merge blk_mq_try_issue_directly and __blk_mq_try_issue_directly into one interface which is able to handle the return value from .queue_rq callback. To make the code clearer, introduce new helpers enum mq_issue_decision and blk_mq_make_decision to decide how to handle the non-issued requests.
Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> --- block/blk-mq.c | 104 +++++++++++++++++++++++++++++++++------------------------ 1 file changed, 61 insertions(+), 43 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c index af5b591..962fdfc 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1729,78 +1729,96 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, return ret; } -static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, +enum mq_issue_decision { + MQ_ISSUE_INSERT_QUEUE, + MQ_ISSUE_END_REQUEST, + MQ_ISSUE_DO_NOTHING, +}; + +static inline enum mq_issue_decision + blk_mq_make_dicision(blk_status_t ret, bool bypass) +{ + enum mq_issue_decision dec; + + switch(ret) { + case BLK_STS_OK: + dec = MQ_ISSUE_DO_NOTHING; + break; + case BLK_STS_DEV_RESOURCE: + case BLK_STS_RESOURCE: + dec = bypass ? MQ_ISSUE_DO_NOTHING : MQ_ISSUE_INSERT_QUEUE; + break; + default: + dec = bypass ? MQ_ISSUE_DO_NOTHING : MQ_ISSUE_END_REQUEST; + break; + } + + return dec; +} + +static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, blk_qc_t *cookie, - bool bypass_insert) + bool bypass) { struct request_queue *q = rq->q; bool run_queue = true; + blk_status_t ret = BLK_STS_RESOURCE; + enum mq_issue_decision dec; + int srcu_idx; + + hctx_lock(hctx, &srcu_idx); /* - * RCU or SRCU read lock is needed before checking quiesced flag. + * hctx_lock is needed before checking quiesced flag. * - * When queue is stopped or quiesced, ignore 'bypass_insert' from - * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller, - * and avoid driver to try to dispatch again. + * When queue is stopped or quiesced, ignore 'bypass', insert + * and return BLK_STS_OK to caller, and avoid driver to try to + * dispatch again. */ if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { run_queue = false; - bypass_insert = false; - goto insert; + bypass = false; + goto out_unlock; } - if (q->elevator && !bypass_insert) - goto insert; + if (q->elevator && !bypass) + goto out_unlock; if (!blk_mq_get_dispatch_budget(hctx)) - goto insert; + goto out_unlock; if (!blk_mq_get_driver_tag(rq)) { blk_mq_put_dispatch_budget(hctx); - goto insert; + goto out_unlock; } - return __blk_mq_issue_directly(hctx, rq, cookie); -insert: - if (bypass_insert) - return BLK_STS_RESOURCE; + ret = __blk_mq_issue_directly(hctx, rq, cookie); - blk_mq_sched_insert_request(rq, false, run_queue, false); - 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); +out_unlock: + hctx_unlock(hctx, srcu_idx); - ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false); - if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) - blk_mq_sched_insert_request(rq, false, true, false); - else if (ret != BLK_STS_OK) + dec = blk_mq_make_dicision(ret, bypass); + switch(dec) { + case MQ_ISSUE_INSERT_QUEUE: + blk_mq_sched_insert_request(rq, false, run_queue, false); + break; + case MQ_ISSUE_END_REQUEST: blk_mq_end_request(rq, ret); + break; + default: + return ret; + } - hctx_unlock(hctx, srcu_idx); + return BLK_STS_OK; } blk_status_t blk_mq_request_issue_directly(struct request *rq) { - blk_status_t ret; - int srcu_idx; struct blk_mq_ctx *ctx = rq->mq_ctx; struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(rq->q, ctx->cpu); - hctx_lock(hctx, &srcu_idx); - ret = __blk_mq_try_issue_directly(hctx, rq, NULL, true); - hctx_unlock(hctx, srcu_idx); - - return ret; + return blk_mq_try_issue_directly(hctx, rq, NULL, true); } void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, @@ -1922,13 +1940,13 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) data.hctx = blk_mq_map_queue(q, same_queue_rq->mq_ctx->cpu); blk_mq_try_issue_directly(data.hctx, same_queue_rq, - &cookie); + &cookie, false); } } else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator && !data.hctx->dispatch_busy)) { blk_mq_put_ctx(data.ctx); blk_mq_bio_to_request(rq, bio); - blk_mq_try_issue_directly(data.hctx, rq, &cookie); + blk_mq_try_issue_directly(data.hctx, rq, &cookie, false); } else { blk_mq_put_ctx(data.ctx); blk_mq_bio_to_request(rq, bio); -- 2.7.4
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