From 0504ca2d5f6ecac30a776186b38283ca1209de68 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Fri, 11 Jan 2013 13:19:27 +0100
Subject: [PATCH] cgroup: Take css_set_lock from cgroup_css_sets_empty()
As indicated in the comment above cgroup_css_sets_empty it needs the
css_set_lock. But neither of the 2 call points have it, so rather then fixing
the callers just take the lock inside cgroup_css_sets_empty().
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Change-Id: If7aea71824f6d0e3f2cc6c1ce236c3ae6be2037b
---
kernel/cgroup.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2f0d7542c0d2..6c443d3aa345 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3954,19 +3954,23 @@ static int cgroup_clear_css_refs(struct cgroup *cgrp)
return !failed;
}
-/* checks if all of the css_sets attached to a cgroup have a refcount of 0.
- * Must be called with css_set_lock held */
+/* Checks if all of the css_sets attached to a cgroup have a refcount of 0. */
static int cgroup_css_sets_empty(struct cgroup *cgrp)
{
struct cg_cgroup_link *link;
+ int retval = 1;
+ read_lock(&css_set_lock);
list_for_each_entry(link, &cgrp->css_sets, cgrp_link_list) {
struct css_set *cg = link->cg;
- if (atomic_read(&cg->refcount) > 0)
- return 0;
+ if (atomic_read(&cg->refcount) > 0) {
+ retval = 0;
+ break;
+ }
}
+ read_unlock(&css_set_lock);
- return 1;
+ return retval;
}
static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
--
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