From: Peng Wang <rocking@whu.edu.cn>
Date: Wed, 3 Jul 2019 02:07:49 +0000 (+0800)
Subject: cgroup: minor tweak for logic to get cgroup css
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a581563f1bef035e4c8d634a1df26dae9140b115;p=linux.git

cgroup: minor tweak for logic to get cgroup css

We could only handle the case that css exists
and css_try_get_online() fails.

Signed-off-by: Peng Wang <rocking@whu.edu.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
---

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 3c3d92d993e8b..21ddf30532355 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -488,7 +488,7 @@ static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
 
 	rcu_read_lock();
 	css = cgroup_css(cgrp, ss);
-	if (!css || !css_tryget_online(css))
+	if (css && !css_tryget_online(css))
 		css = NULL;
 	rcu_read_unlock();