cgroup: remove unnecessary 0 check from css_from_id()

css_idr allocation starts at 1, so index 0 will never point to an item.
css_from_id() currently filters that before asking idr_find(), but
idr_find() would also just return NULL, so this is not needed.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Johannes Weiner <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Tejun Heo <[email protected]>
Cc: Nikolay Borisov <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3108150e47b1a298d9660fd9ec4b3870d9b5ba1d..fa943843a32f62802c28761df59e57bb72456244 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6166,7 +6166,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
 {
        WARN_ON_ONCE(!rcu_read_lock_held());
-       return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
+       return idr_find(&ss->css_idr, id);
 }
 
 /**