From 3b87c6ea671a18fb77709240d658f4201904f8e4 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 2 Nov 2021 23:36:19 +0800 Subject: [PATCH] blk-mq: update hctx->nr_active in blk_mq_end_request_batch() In case of shared tags and none io sched, batched completion still may be run into, and hctx->nr_active is accounted when getting driver tag, so it has to be updated in blk_mq_end_request_batch(). Otherwise, hctx->nr_active may become same with queue depth, then hctx_may_queue() always return false, then io hang is caused. Fixes the issue by updating the counter in batched way. Reported-by: Shinichiro Kawasaki Fixes: f794f3351f26 ("block: add support for blk_mq_end_request_batch()") Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20211102153619.3627505-4-ming.lei@redhat.com Signed-off-by: Jens Axboe --- block/blk-mq.c | 7 +++++++ block/blk-mq.h | 12 +++++++++--- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/block/blk-mq.c b/block/blk-mq.c index 00263d8..c68aa0a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -818,6 +818,13 @@ static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx, { struct request_queue *q = hctx->queue; + /* + * All requests should have been marked as RQF_MQ_INFLIGHT, so + * update hctx->nr_active in batch + */ + if (hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) + __blk_mq_sub_active_requests(hctx, nr_tags); + blk_mq_put_tags(hctx->tags, tag_array, nr_tags); percpu_ref_put_many(&q->q_usage_counter, nr_tags); } diff --git a/block/blk-mq.h b/block/blk-mq.h index 28859fc..cb0b548 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -225,12 +225,18 @@ static inline void __blk_mq_inc_active_requests(struct blk_mq_hw_ctx *hctx) atomic_inc(&hctx->nr_active); } -static inline void __blk_mq_dec_active_requests(struct blk_mq_hw_ctx *hctx) +static inline void __blk_mq_sub_active_requests(struct blk_mq_hw_ctx *hctx, + int val) { if (blk_mq_is_shared_tags(hctx->flags)) - atomic_dec(&hctx->queue->nr_active_requests_shared_tags); + atomic_sub(val, &hctx->queue->nr_active_requests_shared_tags); else - atomic_dec(&hctx->nr_active); + atomic_sub(val, &hctx->nr_active); +} + +static inline void __blk_mq_dec_active_requests(struct blk_mq_hw_ctx *hctx) +{ + __blk_mq_sub_active_requests(hctx, 1); } static inline int __blk_mq_active_requests(struct blk_mq_hw_ctx *hctx) -- 2.7.4