From: Qi Zheng <zhengqi.arch@bytedance.com>

The debugfs_remove_recursive() will wait for debugfs_file_put()
to return, so there is no need to put it after synchronize_srcu()
to wait for the rcu read-side critical section to exit.

Just move it before synchronize_srcu(), which is also convenient
to put the heavy synchronize_srcu() in the delayed work later.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 mm/vmscan.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index eeca83e28c9b..a773e97e152e 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -818,11 +818,11 @@ void unregister_shrinker(struct shrinker *shrinker)
 	debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id);
 	mutex_unlock(&shrinker_mutex);
 
+	shrinker_debugfs_remove(debugfs_entry, debugfs_id);
+
 	atomic_inc(&shrinker_srcu_generation);
 	synchronize_srcu(&shrinker_srcu);
 
-	shrinker_debugfs_remove(debugfs_entry, debugfs_id);
-
 	kfree(shrinker->nr_deferred);
 	shrinker->nr_deferred = NULL;
 }
-- 
2.30.2

On Wed, May 31, 2023 at 09:57:35AM +0000, Qi Zheng wrote:
> From: Qi Zheng <zhengqi.arch@bytedance.com>
> 
> The debugfs_remove_recursive() will wait for debugfs_file_put()
> to return, so there is no need to put it after synchronize_srcu()
> to wait for the rcu read-side critical section to exit.
> 
> Just move it before synchronize_srcu(), which is also convenient
> to put the heavy synchronize_srcu() in the delayed work later.
> 
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---

Afaict, should be a patch independent of this series.

On 2023/5/31 18:49, Christian Brauner wrote:
> On Wed, May 31, 2023 at 09:57:35AM +0000, Qi Zheng wrote:
>> From: Qi Zheng <zhengqi.arch@bytedance.com>
>>
>> The debugfs_remove_recursive() will wait for debugfs_file_put()
>> to return, so there is no need to put it after synchronize_srcu()
>> to wait for the rcu read-side critical section to exit.
>>
>> Just move it before synchronize_srcu(), which is also convenient
>> to put the heavy synchronize_srcu() in the delayed work later.
>>
>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>> ---
> 
> Afaict, should be a patch independent of this series.

OK, will resend as an independent patch.

Thanks,
Qi