diff mbox

block: avoid incorrect bdi_unregiter call in blk_cleanup_queue

Message ID 583FE310.7040607@jp.fujitsu.com (mailing list archive)
State New, archived
Headers show

Commit Message

Masayoshi Mizuma Dec. 1, 2016, 8:45 a.m. UTC
blk_cleanup_queue() should call bdi_unregister() only if WB_registered
is set to bdi->wb.state. Because, blk_cleanup_queue() may be called
before bdi_register() is called, for example, error path.

Signed-off-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>
---
 block/blk-core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Jens Axboe Dec. 1, 2016, 3:04 p.m. UTC | #1
On 12/01/2016 01:45 AM, Masayoshi Mizuma wrote:
> blk_cleanup_queue() should call bdi_unregister() only if WB_registered
> is set to bdi->wb.state. Because, blk_cleanup_queue() may be called
> before bdi_register() is called, for example, error path.

Should this logic be in bdi_unregister() instead?
Masayoshi Mizuma Dec. 2, 2016, 12:37 a.m. UTC | #2
Hi Jens,

On Thu, 1 Dec 2016 08:04:33 -0700 Jens Axboe wrote:
> On 12/01/2016 01:45 AM, Masayoshi Mizuma wrote:
>> blk_cleanup_queue() should call bdi_unregister() only if WB_registered
>> is set to bdi->wb.state. Because, blk_cleanup_queue() may be called
>> before bdi_register() is called, for example, error path.
> 
> Should this logic be in bdi_unregister() instead?

Thank you for pointed it out! I think your suggestion is better.
I will rewrite the patch.

- Masayoshi Mizuma

> 
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diff mbox

Patch

diff --git a/block/blk-core.c b/block/blk-core.c
index 14d7c07..c1ab17e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -595,7 +595,8 @@  void blk_cleanup_queue(struct request_queue *q)
 		q->queue_lock = &q->__queue_lock;
 	spin_unlock_irq(lock);
 
-	bdi_unregister(&q->backing_dev_info);
+	if (test_bit(WB_registered, &q->backing_dev_info.wb.state))
+		bdi_unregister(&q->backing_dev_info);
 
 	/* @q is and will stay empty, shutdown and put */
 	blk_put_queue(q);