Re: [PATCH] cgroup: fix reverse unlock sequence in cgroup_get_sb

[Danny Feng <dfeng@redhat.com>]

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On 07/22/2009 12:03 AM, Paul Menage wrote:
> On Tue, Jul 21, 2009 at 3:25 AM, Xiaotian Feng<dfeng@redhat.com>  wrote:
>> In cgroup_get_sb, the lock sequence is:
>>         mutex_lock(&inode->i_mutex);
>>         mutex_lock(&cgroup->mutex);
>> so the last unlock sequence should be:
>
> Make this "so for consistency the last ..." ?
>
> Maybe make the patch title "Make unlock sequence in cgroup_get_sb
> consistent" so someone looking through the change logs for fixes to
> backport doesn't wrongly thing that this fixes any bug"?
>

Yep, this is a trivial patch.  Modified following your suggestion, thank 
you.

>>         mutex_unlock(&cgroup->mutex);
>>         mutex_unlock(&inode->i_mutex);
>>
>> Signed-off-by: Xiaotian Feng<dfeng@redhat.com>
>
> Acked-by: Paul Menage<menage@google.com>
>
> Paul


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>From ff96b0dc4a5f06a0e5b7f8dfa5df2b93e993302c Mon Sep 17 00:00:00 2001
From: Xiaotian Feng <dfeng@redhat.com>
Date: Tue, 21 Jul 2009 18:06:43 +0800
Subject: [PATCH] cgroup: make unlock sequence in cgroup_get_sb consistent

Make the last unlock sequence consistent with previous unlock sequeue.

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
---
 kernel/cgroup.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3737a68..11ef162 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1140,8 +1140,8 @@ static int cgroup_get_sb(struct file_system_type *fs_type,
 		BUG_ON(root->number_of_cgroups != 1);
 
 		cgroup_populate_dir(root_cgrp);
-		mutex_unlock(&inode->i_mutex);
 		mutex_unlock(&cgroup_mutex);
+		mutex_unlock(&inode->i_mutex);
 	}
 
 	simple_set_mnt(mnt, sb);
-- 
1.6.2.5