From: Johannes Weiner <hannes@cmpxchg.org>
Date: Tue, 26 Jul 2016 22:27:01 +0000 (-0700)
Subject: cgroup: remove unnecessary 0 check from css_from_id()
X-Git-Tag: v4.8-rc1~147^2~1
X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=cb773df88a737d7d7e05ca7ca516414d3fcdcab8;p=cascardo%2Flinux.git

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/20160617162427.GC19084@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3108150e47b1..fa943843a32f 100644
--- 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);
 }
 
 /**