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Mon, 29 Oct 2018 09:35:25 -0700 (PDT) From: Jens Axboe To: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org Cc: Jens Axboe Subject: [PATCH 19/29] block: remove non mq parts from the flush code Date: Mon, 29 Oct 2018 10:34:34 -0600 Message-Id: <20181029163444.9940-20-axboe@kernel.dk> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181029163444.9940-1-axboe@kernel.dk> References: <20181029163444.9940-1-axboe@kernel.dk> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe --- block/blk-flush.c | 154 +++++++++------------------------------------- block/blk.h | 4 +- 2 files changed, 31 insertions(+), 127 deletions(-) diff --git a/block/blk-flush.c b/block/blk-flush.c index 8b44b86779da..9baa9a119447 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -134,16 +134,8 @@ static void blk_flush_restore_request(struct request *rq) static bool blk_flush_queue_rq(struct request *rq, bool add_front) { - if (rq->q->mq_ops) { - blk_mq_add_to_requeue_list(rq, add_front, true); - return false; - } else { - if (add_front) - list_add(&rq->queuelist, &rq->q->queue_head); - else - list_add_tail(&rq->queuelist, &rq->q->queue_head); - return true; - } + blk_mq_add_to_requeue_list(rq, add_front, true); + return false; } /** @@ -204,10 +196,7 @@ static bool blk_flush_complete_seq(struct request *rq, BUG_ON(!list_empty(&rq->queuelist)); list_del_init(&rq->flush.list); blk_flush_restore_request(rq); - if (q->mq_ops) - blk_mq_end_request(rq, error); - else - __blk_end_request_all(rq, error); + blk_mq_end_request(rq, error); break; default: @@ -226,20 +215,17 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error) struct request *rq, *n; unsigned long flags = 0; struct blk_flush_queue *fq = blk_get_flush_queue(q, flush_rq->mq_ctx); + struct blk_mq_hw_ctx *hctx; - if (q->mq_ops) { - struct blk_mq_hw_ctx *hctx; - - /* release the tag's ownership to the req cloned from */ - spin_lock_irqsave(&fq->mq_flush_lock, flags); - hctx = blk_mq_map_queue(q, flush_rq->mq_ctx->cpu); - if (!q->elevator) { - blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq); - flush_rq->tag = -1; - } else { - blk_mq_put_driver_tag_hctx(hctx, flush_rq); - flush_rq->internal_tag = -1; - } + /* release the tag's ownership to the req cloned from */ + spin_lock_irqsave(&fq->mq_flush_lock, flags); + hctx = blk_mq_map_queue(q, flush_rq->mq_ctx->cpu); + if (!q->elevator) { + blk_mq_tag_set_rq(hctx, flush_rq->tag, fq->orig_rq); + flush_rq->tag = -1; + } else { + blk_mq_put_driver_tag_hctx(hctx, flush_rq); + flush_rq->internal_tag = -1; } running = &fq->flush_queue[fq->flush_running_idx]; @@ -248,9 +234,6 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error) /* account completion of the flush request */ fq->flush_running_idx ^= 1; - if (!q->mq_ops) - elv_completed_request(q, flush_rq); - /* and push the waiting requests to the next stage */ list_for_each_entry_safe(rq, n, running, flush.list) { unsigned int seq = blk_flush_cur_seq(rq); @@ -259,24 +242,8 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error) queued |= blk_flush_complete_seq(rq, fq, seq, error); } - /* - * Kick the queue to avoid stall for two cases: - * 1. Moving a request silently to empty queue_head may stall the - * queue. - * 2. When flush request is running in non-queueable queue, the - * queue is hold. Restart the queue after flush request is finished - * to avoid stall. - * This function is called from request completion path and calling - * directly into request_fn may confuse the driver. Always use - * kblockd. - */ - if (queued || fq->flush_queue_delayed) { - WARN_ON(q->mq_ops); - blk_run_queue_async(q); - } fq->flush_queue_delayed = 0; - if (q->mq_ops) - spin_unlock_irqrestore(&fq->mq_flush_lock, flags); + spin_unlock_irqrestore(&fq->mq_flush_lock, flags); } /** @@ -301,6 +268,7 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq, struct request *first_rq = list_first_entry(pending, struct request, flush.list); struct request *flush_rq = fq->flush_rq; + struct blk_mq_hw_ctx *hctx; /* C1 described at the top of this file */ if (fq->flush_pending_idx != fq->flush_running_idx || list_empty(pending)) @@ -334,19 +302,15 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq, * In case of IO scheduler, flush rq need to borrow scheduler tag * just for cheating put/get driver tag. */ - if (q->mq_ops) { - struct blk_mq_hw_ctx *hctx; - - flush_rq->mq_ctx = first_rq->mq_ctx; - - if (!q->elevator) { - fq->orig_rq = first_rq; - flush_rq->tag = first_rq->tag; - hctx = blk_mq_map_queue(q, first_rq->mq_ctx->cpu); - blk_mq_tag_set_rq(hctx, first_rq->tag, flush_rq); - } else { - flush_rq->internal_tag = first_rq->internal_tag; - } + flush_rq->mq_ctx = first_rq->mq_ctx; + + if (!q->elevator) { + fq->orig_rq = first_rq; + flush_rq->tag = first_rq->tag; + hctx = blk_mq_map_queue(q, first_rq->mq_ctx->cpu); + blk_mq_tag_set_rq(hctx, first_rq->tag, flush_rq); + } else { + flush_rq->internal_tag = first_rq->internal_tag; } flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH; @@ -358,49 +322,6 @@ static bool blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq, return blk_flush_queue_rq(flush_rq, false); } -static void flush_data_end_io(struct request *rq, blk_status_t error) -{ - struct request_queue *q = rq->q; - struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); - - lockdep_assert_held(q->queue_lock); - - /* - * Updating q->in_flight[] here for making this tag usable - * early. Because in blk_queue_start_tag(), - * q->in_flight[BLK_RW_ASYNC] is used to limit async I/O and - * reserve tags for sync I/O. - * - * More importantly this way can avoid the following I/O - * deadlock: - * - * - suppose there are 40 fua requests comming to flush queue - * and queue depth is 31 - * - 30 rqs are scheduled then blk_queue_start_tag() can't alloc - * tag for async I/O any more - * - all the 30 rqs are completed before FLUSH_PENDING_TIMEOUT - * and flush_data_end_io() is called - * - the other rqs still can't go ahead if not updating - * q->in_flight[BLK_RW_ASYNC] here, meantime these rqs - * are held in flush data queue and make no progress of - * handling post flush rq - * - only after the post flush rq is handled, all these rqs - * can be completed - */ - - elv_completed_request(q, rq); - - /* for avoiding double accounting */ - rq->rq_flags &= ~RQF_STARTED; - - /* - * After populating an empty queue, kick it to avoid stall. Read - * the comment in flush_end_io(). - */ - if (blk_flush_complete_seq(rq, fq, REQ_FSEQ_DATA, error)) - blk_run_queue_async(q); -} - static void mq_flush_data_end_io(struct request *rq, blk_status_t error) { struct request_queue *q = rq->q; @@ -443,9 +364,6 @@ void blk_insert_flush(struct request *rq) unsigned int policy = blk_flush_policy(fflags, rq); struct blk_flush_queue *fq = blk_get_flush_queue(q, rq->mq_ctx); - if (!q->mq_ops) - lockdep_assert_held(q->queue_lock); - /* * @policy now records what operations need to be done. Adjust * REQ_PREFLUSH and FUA for the driver. @@ -468,10 +386,7 @@ void blk_insert_flush(struct request *rq) * complete the request. */ if (!policy) { - if (q->mq_ops) - blk_mq_end_request(rq, 0); - else - __blk_end_request(rq, 0, 0); + blk_mq_end_request(rq, 0); return; } @@ -484,10 +399,7 @@ void blk_insert_flush(struct request *rq) */ if ((policy & REQ_FSEQ_DATA) && !(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) { - if (q->mq_ops) - blk_mq_request_bypass_insert(rq, false); - else - list_add_tail(&rq->queuelist, &q->queue_head); + blk_mq_request_bypass_insert(rq, false); return; } @@ -499,17 +411,12 @@ void blk_insert_flush(struct request *rq) INIT_LIST_HEAD(&rq->flush.list); rq->rq_flags |= RQF_FLUSH_SEQ; rq->flush.saved_end_io = rq->end_io; /* Usually NULL */ - if (q->mq_ops) { - rq->end_io = mq_flush_data_end_io; - spin_lock_irq(&fq->mq_flush_lock); - blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0); - spin_unlock_irq(&fq->mq_flush_lock); - return; - } - rq->end_io = flush_data_end_io; + rq->end_io = mq_flush_data_end_io; + spin_lock_irq(&fq->mq_flush_lock); blk_flush_complete_seq(rq, fq, REQ_FSEQ_ACTIONS & ~policy, 0); + spin_unlock_irq(&fq->mq_flush_lock); } /** @@ -575,8 +482,7 @@ struct blk_flush_queue *blk_alloc_flush_queue(struct request_queue *q, if (!fq) goto fail; - if (q->mq_ops) - spin_lock_init(&fq->mq_flush_lock); + spin_lock_init(&fq->mq_flush_lock); rq_sz = round_up(rq_sz + cmd_size, cache_line_size()); fq->flush_rq = kzalloc_node(rq_sz, flags, node); diff --git a/block/blk.h b/block/blk.h index a1841b8ff129..57a302bf5a70 100644 --- a/block/blk.h +++ b/block/blk.h @@ -114,9 +114,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q) static inline struct blk_flush_queue *blk_get_flush_queue( struct request_queue *q, struct blk_mq_ctx *ctx) { - if (q->mq_ops) - return blk_mq_map_queue(q, ctx->cpu)->fq; - return q->fq; + return blk_mq_map_queue(q, ctx->cpu)->fq; } static inline void __blk_get_queue(struct request_queue *q)