[PATCH] cgroup: minor tweak for logic to get cgroup css

[Peng Wang]

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

Signed-off-by: Peng Wang <rock...@whu.edu.cn>
---
 kernel/cgroup/cgroup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index bf9dbffd46b1..a988d77f6c6d 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();
 
-- 
2.19.1