From 4e2f62e566b5bddec00682f36a404e05a3b64b6a Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 1 Jul 2020 22:58:32 -0600 Subject: Revert "blk-mq: put driver tag when this request is completed" This reverts commits the following commits: 37f4a24c2469a10a4c16c641671bd766e276cf9f 723bf178f158abd1ce6069cb049581b3cb003aab 36a3df5a4574d5ddf59804fcd0c4e9654c514d9a The last one is the culprit, but we have to go a bit deeper to get this to revert cleanly. There's been a report that this breaks some MMC setups [1], and also causes an issue with swap [2]. Until this can be figured out, revert the offending commits. [1] https://lore.kernel.org/linux-block/57fb09b1-54ba-f3aa-f82c-d709b0e6b281@samsung.com/ [2] https://lore.kernel.org/linux-block/20200702043721.GA1087@lca.pw/ Reported-by: Marek Szyprowski Reported-by: Qian Cai Signed-off-by: Jens Axboe --- block/blk-flush.c | 23 +++++++++++++++++------ block/blk-mq-tag.h | 12 ++++++++++++ block/blk-mq.c | 52 ++++++++++++++++------------------------------------ block/blk-mq.h | 20 ++++++++++++++++++++ block/blk.h | 5 +++++ 5 files changed, 70 insertions(+), 42 deletions(-) (limited to 'block') diff --git a/block/blk-flush.c b/block/blk-flush.c index e756db088d84..15ae0155ec07 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -236,10 +236,13 @@ static void flush_end_io(struct request *flush_rq, blk_status_t error) error = fq->rq_status; hctx = flush_rq->mq_hctx; - if (!q->elevator) - flush_rq->tag = BLK_MQ_NO_TAG; - else - flush_rq->internal_tag = BLK_MQ_NO_TAG; + 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(flush_rq); + flush_rq->internal_tag = -1; + } running = &fq->flush_queue[fq->flush_running_idx]; BUG_ON(fq->flush_pending_idx == fq->flush_running_idx); @@ -313,10 +316,13 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq, flush_rq->mq_ctx = first_rq->mq_ctx; flush_rq->mq_hctx = first_rq->mq_hctx; - if (!q->elevator) + if (!q->elevator) { + fq->orig_rq = first_rq; flush_rq->tag = first_rq->tag; - else + blk_mq_tag_set_rq(flush_rq->mq_hctx, first_rq->tag, flush_rq); + } else { flush_rq->internal_tag = first_rq->internal_tag; + } flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH; flush_rq->cmd_flags |= (flags & REQ_DRV) | (flags & REQ_FAILFAST_MASK); @@ -335,6 +341,11 @@ static void mq_flush_data_end_io(struct request *rq, blk_status_t error) unsigned long flags; struct blk_flush_queue *fq = blk_get_flush_queue(q, ctx); + if (q->elevator) { + WARN_ON(rq->tag < 0); + blk_mq_put_driver_tag(rq); + } + /* * After populating an empty queue, kick it to avoid stall. Read * the comment in flush_end_io(). diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h index b1acac518c4e..3945c7f5b944 100644 --- a/block/blk-mq-tag.h +++ b/block/blk-mq-tag.h @@ -101,6 +101,18 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, return atomic_read(&hctx->nr_active) < depth; } +/* + * This helper should only be used for flush request to share tag + * with the request cloned from, and both the two requests can't be + * in flight at the same time. The caller has to make sure the tag + * can't be freed. + */ +static inline void blk_mq_tag_set_rq(struct blk_mq_hw_ctx *hctx, + unsigned int tag, struct request *rq) +{ + hctx->tags->rqs[tag] = rq; +} + static inline bool blk_mq_tag_is_reserved(struct blk_mq_tags *tags, unsigned int tag) { diff --git a/block/blk-mq.c b/block/blk-mq.c index 948987e9b6ab..abcf590f6238 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -277,20 +277,26 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, { struct blk_mq_tags *tags = blk_mq_tags_from_data(data); struct request *rq = tags->static_rqs[tag]; + req_flags_t rq_flags = 0; if (data->q->elevator) { rq->tag = BLK_MQ_NO_TAG; rq->internal_tag = tag; } else { + if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) { + rq_flags = RQF_MQ_INFLIGHT; + atomic_inc(&data->hctx->nr_active); + } rq->tag = tag; rq->internal_tag = BLK_MQ_NO_TAG; + data->hctx->tags->rqs[rq->tag] = rq; } /* csd/requeue_work/fifo_time is initialized before use */ rq->q = data->q; rq->mq_ctx = data->ctx; rq->mq_hctx = data->hctx; - rq->rq_flags = 0; + rq->rq_flags = rq_flags; rq->cmd_flags = data->cmd_flags; if (data->flags & BLK_MQ_REQ_PREEMPT) rq->rq_flags |= RQF_PREEMPT; @@ -660,32 +666,10 @@ static inline bool blk_mq_complete_need_ipi(struct request *rq) return cpu_online(rq->mq_ctx->cpu); } -static void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx, - struct request *rq) -{ - blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag); - rq->tag = BLK_MQ_NO_TAG; - - if (rq->rq_flags & RQF_MQ_INFLIGHT) { - rq->rq_flags &= ~RQF_MQ_INFLIGHT; - atomic_dec(&hctx->nr_active); - } -} - -static inline void blk_mq_put_driver_tag(struct request *rq) -{ - if (rq->tag == BLK_MQ_NO_TAG || rq->internal_tag == BLK_MQ_NO_TAG) - return; - - __blk_mq_put_driver_tag(rq->mq_hctx, rq); -} - bool blk_mq_complete_request_remote(struct request *rq) { WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); - blk_mq_put_driver_tag(rq); - /* * For a polled request, always complete locallly, it's pointless * to redirect the completion. @@ -1121,10 +1105,9 @@ static bool __blk_mq_get_driver_tag(struct request *rq) { struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags; unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags; + bool shared = blk_mq_tag_busy(rq->mq_hctx); int tag; - blk_mq_tag_busy(rq->mq_hctx); - if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) { bt = &rq->mq_hctx->tags->breserved_tags; tag_offset = 0; @@ -1137,22 +1120,19 @@ static bool __blk_mq_get_driver_tag(struct request *rq) return false; rq->tag = tag + tag_offset; + if (shared) { + rq->rq_flags |= RQF_MQ_INFLIGHT; + atomic_inc(&rq->mq_hctx->nr_active); + } + rq->mq_hctx->tags->rqs[rq->tag] = rq; return true; } static bool blk_mq_get_driver_tag(struct request *rq) { - struct blk_mq_hw_ctx *hctx = rq->mq_hctx; - - if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_get_driver_tag(rq)) - return false; - - if (hctx->flags & BLK_MQ_F_TAG_SHARED) { - rq->rq_flags |= RQF_MQ_INFLIGHT; - atomic_inc(&hctx->nr_active); - } - hctx->tags->rqs[rq->tag] = rq; - return true; + if (rq->tag != BLK_MQ_NO_TAG) + return true; + return __blk_mq_get_driver_tag(rq); } static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, diff --git a/block/blk-mq.h b/block/blk-mq.h index 3661e821d460..863a2f3346d4 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -193,6 +193,26 @@ static inline bool blk_mq_get_dispatch_budget(struct request_queue *q) return true; } +static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx, + struct request *rq) +{ + blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag); + rq->tag = BLK_MQ_NO_TAG; + + if (rq->rq_flags & RQF_MQ_INFLIGHT) { + rq->rq_flags &= ~RQF_MQ_INFLIGHT; + atomic_dec(&hctx->nr_active); + } +} + +static inline void blk_mq_put_driver_tag(struct request *rq) +{ + if (rq->tag == BLK_MQ_NO_TAG || rq->internal_tag == BLK_MQ_NO_TAG) + return; + + __blk_mq_put_driver_tag(rq->mq_hctx, rq); +} + static inline void blk_mq_clear_mq_map(struct blk_mq_queue_map *qmap) { int cpu; diff --git a/block/blk.h b/block/blk.h index 9dcf51c94096..94f7c084f68f 100644 --- a/block/blk.h +++ b/block/blk.h @@ -25,6 +25,11 @@ struct blk_flush_queue { struct list_head flush_data_in_flight; struct request *flush_rq; + /* + * flush_rq shares tag with this rq, both can't be active + * at the same time + */ + struct request *orig_rq; struct lock_class_key key; spinlock_t mq_flush_lock; }; -- cgit v1.2.3