[PATCH] cgroup: remove incorrect check on the return value of css_alloc

[Xiongwei Song]

The function css_alloc never return NULL, it may return normal pointer or
error codes that made by ERR_PTR, so !css is always false, we need use
IS_ERR to check it, and if this is true, we should use ERR_CAST handle it.

Signed-off-by: Xiongwei Song <sxwj...@me.com>
---
 kernel/cgroup/cgroup.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index adac5b91d2b8..a442fd9ad744 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4728,10 +4728,8 @@ static struct cgroup_subsys_state *css_create(struct 
cgroup *cgrp,
        lockdep_assert_held(&cgroup_mutex);
 
        css = ss->css_alloc(parent_css);
-       if (!css)
-               css = ERR_PTR(-ENOMEM);
        if (IS_ERR(css))
-               return css;
+               return ERR_CAST(css);
 
        init_and_link_css(css, ss, cgrp);
 
-- 
2.15.1