From: Ming Lei <ming.lei@redhat.com>
Date: Thu, 30 Nov 2017 07:56:35 +0800
Subject: [PATCH] block: drain queue before waiting for q_usage_counter
becoming zero
References: bsc#1077989
Git-commit: 454be724f6f99cc7e7bbf15067128be9868186c6
Patch-mainline: v4.15-rc8
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 <wenxiong@us.ibm.com>
Tested-by: "chenxiang (M)" <chenxiang66@hisilicon.com>
Tested-by: Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
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 a886a576e63b..a743840c43ed 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -531,6 +531,13 @@ 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
@@ -658,8 +665,6 @@ 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 be6f611fecd9..c43a51ede1f8 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 fde8b351c166..07f3836c21c9 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -362,4 +362,6 @@ 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 */
--
2.12.3