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 blk_mq_make_decision and enum mq_decision.
Signed-off-by: Jianchao Wang <[email protected]> --- block/blk-mq.c | 104 ++++++++++++++++++++++++++++++----------------------- block/blk-mq.c.rej | 60 +++++++++++++++++++++++++++++++ 2 files changed, 120 insertions(+), 44 deletions(-) create mode 100644 block/blk-mq.c.rej diff --git a/block/blk-mq.c b/block/blk-mq.c index dcf10e3..0f6328b 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1711,7 +1711,6 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, switch (ret) { case BLK_STS_OK: blk_mq_update_dispatch_busy(hctx, false); - *cookie = new_cookie; break; case BLK_STS_RESOURCE: case BLK_STS_DEV_RESOURCE: @@ -1720,86 +1719,103 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, break; default: blk_mq_update_dispatch_busy(hctx, false); - *cookie = BLK_QC_T_NONE; + new_cookie = BLK_QC_T_NONE; break; } + if (cookie) + *cookie = new_cookie; return ret; } -static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, +enum mq_decision { + MQ_INSERT_QUEUE, + MQ_END_REQUEST, + MQ_DO_NOTHING, +}; + +static inline enum mq_decision + blk_mq_make_dicision(blk_status_t ret, bool bypass_insert) +{ + enum mq_decision dec; + + switch(ret) { + case BLK_STS_OK: + dec = MQ_DO_NOTHING; + break; + case BLK_STS_DEV_RESOURCE: + case BLK_STS_RESOURCE: + dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE; + break; + default: + dec = bypass_insert ? MQ_DO_NOTHING : MQ_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) { struct request_queue *q = rq->q; bool run_queue = true; + enum mq_decision dec; + blk_status_t ret = BLK_STS_RESOURCE; + 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; + goto out_unlock; } if (q->elevator && !bypass_insert) - goto insert; + 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; - - 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); + ret = __blk_mq_issue_directly(hctx, rq, cookie); +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_insert); + switch(dec) { + case MQ_INSERT_QUEUE: + blk_mq_sched_insert_request(rq, false, run_queue, false); + break; + case MQ_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; - blk_qc_t unused_cookie; 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, &unused_cookie, 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, @@ -1921,13 +1937,13 @@ 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); diff --git a/block/blk-mq.c.rej b/block/blk-mq.c.rej new file mode 100644 index 0000000..7813cd9 --- /dev/null +++ b/block/blk-mq.c.rej @@ -0,0 +1,60 @@ +--- block/blk-mq.c ++++ block/blk-mq.c +@@ -1728,13 +1728,14 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, + } + + enum mq_decision { ++ MQ_INSERT_DISPATCH, + MQ_INSERT_QUEUE, + MQ_END_REQUEST, + MQ_DO_NOTHING, + }; + +-static inline enum mq_decision +- blk_mq_make_dicision(blk_status_t ret, bool bypass_insert) ++static inline enum mq_decision blk_mq_make_dicision(blk_status_t ret, ++ bool bypass_insert, bool force_insert) + { + enum mq_decision dec; + +@@ -1744,7 +1745,10 @@ static inline enum mq_decision + break; + case BLK_STS_DEV_RESOURCE: + case BLK_STS_RESOURCE: +- dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE; ++ if (force_insert) ++ dec = bypass_insert ? MQ_INSERT_DISPATCH : MQ_INSERT_QUEUE; ++ else ++ dec = bypass_insert ? MQ_DO_NOTHING : MQ_INSERT_QUEUE; + break; + default: + dec = bypass_insert ? MQ_DO_NOTHING : MQ_END_REQUEST; +@@ -1760,7 +1764,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, + bool bypass_insert) + { + struct request_queue *q = rq->q; +- bool run_queue = true; ++ bool run_queue = true, force_insert = false; + enum mq_decision dec; + blk_status_t ret = BLK_STS_RESOURCE; + int srcu_idx; +@@ -1775,7 +1779,7 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, + */ + if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { + run_queue = false; +- bypass_insert = false; ++ force_insert = true; + goto out_unlock; + } + +@@ -1795,7 +1799,10 @@ static blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, + hctx_unlock(hctx, srcu_idx); + + dec = blk_mq_make_dicision(ret, bypass_insert); + switch(pos) { ++ case MQ_INSERT_DISPATCH: ++ blk_mq_request_bypass_insert(rq, run_queue); ++ break; + case MQ_INSERT_QUEUE: + blk_mq_sched_insert_request(rq, false, run_queue, false); + break; -- 2.7.4
