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From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: <linux-mm@kvack.org>, <linux-block@vger.kernel.org>
Subject: [PATCH v2] block: avoid incorrect bdi_unregiter call
Date: Fri, 2 Dec 2016 14:08:34 +0900	[thread overview]
Message-ID: <584101D2.4090200@jp.fujitsu.com> (raw)

bdi_unregister() should be called after bdi_register() is called,
so we should check whether WB_registered flag is set.

For example of the situation, error path in device driver may call
blk_cleanup_queue() before the driver calls bdi_register().

Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
---
 mm/backing-dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8fde443..f8b07d4 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -853,6 +853,9 @@ static void bdi_remove_from_list(struct backing_dev_info *bdi)
 
 void bdi_unregister(struct backing_dev_info *bdi)
 {
+	if (!test_bit(WB_registered, &bdi->wb.state))
+		return;
+
 	/* make sure nobody finds us on the bdi_list anymore */
 	bdi_remove_from_list(bdi);
 	wb_shutdown(&bdi->wb);
-- 
1.8.3.1

WARNING: multiple messages have this Message-ID (diff)
From: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: linux-mm@kvack.org, linux-block@vger.kernel.org
Subject: [PATCH v2] block: avoid incorrect bdi_unregiter call
Date: Fri, 2 Dec 2016 14:08:34 +0900	[thread overview]
Message-ID: <584101D2.4090200@jp.fujitsu.com> (raw)

bdi_unregister() should be called after bdi_register() is called,
so we should check whether WB_registered flag is set.

For example of the situation, error path in device driver may call
blk_cleanup_queue() before the driver calls bdi_register().

Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
---
 mm/backing-dev.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 8fde443..f8b07d4 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -853,6 +853,9 @@ static void bdi_remove_from_list(struct backing_dev_info *bdi)
 
 void bdi_unregister(struct backing_dev_info *bdi)
 {
+	if (!test_bit(WB_registered, &bdi->wb.state))
+		return;
+
 	/* make sure nobody finds us on the bdi_list anymore */
 	bdi_remove_from_list(bdi);
 	wb_shutdown(&bdi->wb);
-- 
1.8.3.1

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             reply	other threads:[~2016-12-02  5:09 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-02  5:08 Masayoshi Mizuma [this message]
2016-12-02  5:08 ` [PATCH v2] block: avoid incorrect bdi_unregiter call Masayoshi Mizuma
2016-12-16  5:00 ` Masayoshi Mizuma
2016-12-16  5:00   ` Masayoshi Mizuma

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