[PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Wang Jianchao (Kuaishou)]

From: Wang Jianchao <wangjianchao@kuaishou.com>

When __alloc_disk_node() failed, there will not not del_gendisk()
any more, then resource in rqos policies is leaked. Add rq_qos_exit()
into blk_cleanup_queue(). rqos is removed from the list, so needn't
to worry .exit is called twice.

Fixes: commit 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
Suggested-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
---
 block/blk-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index d93e3bb9a769..108c7207d048 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -50,6 +50,7 @@
 #include "blk-mq-sched.h"
 #include "blk-pm.h"
 #include "blk-throttle.h"
+#include "blk-rq-qos.h"
 
 struct dentry *blk_debugfs_root;
 
@@ -322,6 +323,8 @@ void blk_cleanup_queue(struct request_queue *q)
 
 	blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
 
+	rq_qos_exit(q);
+
 	blk_sync_queue(q);
 	if (queue_is_mq(q)) {
 		blk_mq_cancel_work_sync(q);
-- 
2.17.1

Re: [PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Bart Van Assche]

On 2/16/22 03:32, Wang Jianchao (Kuaishou) wrote:
> From: Wang Jianchao <wangjianchao@kuaishou.com>
> 
> When __alloc_disk_node() failed, there will not not del_gendisk()

Please use the present tense for patch descriptions (failed -> fails).

Anyway:

Reviewed-by: Bart Van Assche <bvanassche@acm.org>

Re: [PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Jens Axboe]

On Wed, 16 Feb 2022 19:32:12 +0800, Wang Jianchao (Kuaishou) wrote:
> From: Wang Jianchao <wangjianchao@kuaishou.com>
> 
> When __alloc_disk_node() failed, there will not not del_gendisk()
> any more, then resource in rqos policies is leaked. Add rq_qos_exit()
> into blk_cleanup_queue(). rqos is removed from the list, so needn't
> to worry .exit is called twice.
> 
> [...]

Applied, thanks!

[1/1] blk: do rq_qos_exit in blk_cleanup_queue
      commit: 20d41d9e993735b996175d087148d9de1fc94ac0

Best regards,
-- 
Jens Axboe

Re: [PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Christoph Hellwig]

On Wed, Feb 16, 2022 at 07:32:12PM +0800, Wang Jianchao (Kuaishou) wrote:
> From: Wang Jianchao <wangjianchao@kuaishou.com>
> 
> When __alloc_disk_node() failed, there will not not del_gendisk()
> any more, then resource in rqos policies is leaked. Add rq_qos_exit()
> into blk_cleanup_queue(). rqos is removed from the list, so needn't
> to worry .exit is called twice.
> 
> Fixes: commit 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
> Suggested-by: Bart Van Assche <bart.vanassche@wdc.com>
> Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>

Ming had a pending patch to move it into disk_release instead, which
I think is the right place.

Re: [PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Jens Axboe]

On 2/17/22 12:48 AM, Christoph Hellwig wrote:
> On Wed, Feb 16, 2022 at 07:32:12PM +0800, Wang Jianchao (Kuaishou) wrote:
>> From: Wang Jianchao <wangjianchao@kuaishou.com>
>>
>> When __alloc_disk_node() failed, there will not not del_gendisk()
>> any more, then resource in rqos policies is leaked. Add rq_qos_exit()
>> into blk_cleanup_queue(). rqos is removed from the list, so needn't
>> to worry .exit is called twice.
>>
>> Fixes: commit 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
>> Suggested-by: Bart Van Assche <bart.vanassche@wdc.com>
>> Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
> 
> Ming had a pending patch to move it into disk_release instead, which
> I think is the right place.

I missed that patch and can't seem to find it, do you have a link?

-- 
Jens Axboe

Re: [PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Christoph Hellwig]

On Thu, Feb 17, 2022 at 06:34:02AM -0700, Jens Axboe wrote:
> On 2/17/22 12:48 AM, Christoph Hellwig wrote:
> > On Wed, Feb 16, 2022 at 07:32:12PM +0800, Wang Jianchao (Kuaishou) wrote:
> >> From: Wang Jianchao <wangjianchao@kuaishou.com>
> >>
> >> When __alloc_disk_node() failed, there will not not del_gendisk()
> >> any more, then resource in rqos policies is leaked. Add rq_qos_exit()
> >> into blk_cleanup_queue(). rqos is removed from the list, so needn't
> >> to worry .exit is called twice.
> >>
> >> Fixes: commit 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
> >> Suggested-by: Bart Van Assche <bart.vanassche@wdc.com>
> >> Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
> > 
> > Ming had a pending patch to move it into disk_release instead, which
> > I think is the right place.
> 
> I missed that patch and can't seem to find it, do you have a link?

[PATCH V2 12/13] block: move rq_qos_exit() into disk_release()

from Jan 22.  Although it would need a rebase so it can be applied
without the preceding patches.

Re: [PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Jens Axboe]

On 2/17/22 7:03 AM, Christoph Hellwig wrote:
> On Thu, Feb 17, 2022 at 06:34:02AM -0700, Jens Axboe wrote:
>> On 2/17/22 12:48 AM, Christoph Hellwig wrote:
>>> On Wed, Feb 16, 2022 at 07:32:12PM +0800, Wang Jianchao (Kuaishou) wrote:
>>>> From: Wang Jianchao <wangjianchao@kuaishou.com>
>>>>
>>>> When __alloc_disk_node() failed, there will not not del_gendisk()
>>>> any more, then resource in rqos policies is leaked. Add rq_qos_exit()
>>>> into blk_cleanup_queue(). rqos is removed from the list, so needn't
>>>> to worry .exit is called twice.
>>>>
>>>> Fixes: commit 8e141f9eb803 ("block: drain file system I/O on del_gendisk")
>>>> Suggested-by: Bart Van Assche <bart.vanassche@wdc.com>
>>>> Signed-off-by: Wang Jianchao <wangjianchao@kuaishou.com>
>>>
>>> Ming had a pending patch to move it into disk_release instead, which
>>> I think is the right place.
>>
>> I missed that patch and can't seem to find it, do you have a link?
> 
> [PATCH V2 12/13] block: move rq_qos_exit() into disk_release()
> 
> from Jan 22.  Although it would need a rebase so it can be applied
> without the preceding patches.

Can someone respin that for 5.17 then?

-- 
Jens Axboe

Re: [PATCH] blk: do rq_qos_exit in blk_cleanup_queue

[Christoph Hellwig]

On Thu, Feb 17, 2022 at 07:55:16AM -0700, Jens Axboe wrote:
> > from Jan 22.  Although it would need a rebase so it can be applied
> > without the preceding patches.
> 
> Can someone respin that for 5.17 then?

I looked at it and it I don't think we can do that without a lot of
the prep patches.

That being said I think this version of the patch also is buggy, we
want the policies shut down in del_gendisk with the queue frozen for
normal operation.

I guess until we can move the initialization and teardown entirely
to the gendisk as in Ming's more complex series we need to keep the
call in del_gendisk and also do it in blk_cleanup_queue.  For the
normal shutdown on disk that were life del_gendisk does the all the
work on the frozen queue, while for queues that never had a disk
blk_cleanup_queue will clean up the unused rq_qos.