From 454be724f6f99cc7e7bbf15067128be9868186c6 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 30 Nov 2017 07:56:35 +0800 Subject: [PATCH] block: drain queue before waiting for q_usage_counter becoming zero Now we track legacy requests with .q_usage_counter in commit 055f6e18e08f ("block: Make q_usage_counter also track legacy requests"), but that commit never runs and drains legacy queue before waiting for this counter becoming zero, then IO hang is caused in the test of pulling disk during IO. This patch fixes the issue by draining requests before waiting for q_usage_counter becoming zero, both Mauricio and chenxiang reported this issue, and observed that it can be fixed by this patch. Link: https://marc.info/?l=linux-block&m=151192424731797&w=2 Fixes: 055f6e18e08f("block: Make q_usage_counter also track legacy requests") Cc: Wen Xiong Tested-by: "chenxiang (M)" Tested-by: Mauricio Faria de Oliveira Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-core.c | 9 +++++++-- block/blk-mq.c | 2 ++ block/blk.h | 2 ++ 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index b8881750a3ac..3ba4326a63b5 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -562,6 +562,13 @@ static void __blk_drain_queue(struct request_queue *q, bool drain_all) } } +void blk_drain_queue(struct request_queue *q) +{ + spin_lock_irq(q->queue_lock); + __blk_drain_queue(q, true); + spin_unlock_irq(q->queue_lock); +} + /** * blk_queue_bypass_start - enter queue bypass mode * @q: queue of interest @@ -689,8 +696,6 @@ void blk_cleanup_queue(struct request_queue *q) */ blk_freeze_queue(q); spin_lock_irq(lock); - if (!q->mq_ops) - __blk_drain_queue(q, true); queue_flag_set(QUEUE_FLAG_DEAD, q); spin_unlock_irq(lock); diff --git a/block/blk-mq.c b/block/blk-mq.c index 11097477eeab..3d3797327491 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -161,6 +161,8 @@ void blk_freeze_queue(struct request_queue *q) * exported to drivers as the only user for unfreeze is blk_mq. */ blk_freeze_queue_start(q); + if (!q->mq_ops) + blk_drain_queue(q); blk_mq_freeze_queue_wait(q); } diff --git a/block/blk.h b/block/blk.h index 3f1446937aec..442098aa9463 100644 --- a/block/blk.h +++ b/block/blk.h @@ -330,4 +330,6 @@ static inline void blk_queue_bounce(struct request_queue *q, struct bio **bio) } #endif /* CONFIG_BOUNCE */ +extern void blk_drain_queue(struct request_queue *q); + #endif /* BLK_INTERNAL_H */