From: Andrey Ignatov <rdna@fb.com>
Date: Sat, 22 Sep 2018 00:03:27 +0000 (-0700)
Subject: cgroup: Simplify cgroup_ancestor
X-Git-Tag: v4.20-rc1~114^2~2
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=808c43b7c7f70360ed7b9e43e2cf980f388e71fa;p=linux-2.6-block.git

cgroup: Simplify cgroup_ancestor

Simplify cgroup_ancestor function. This is follow-up for
commit 7723628101aa ("bpf: Introduce bpf_skb_ancestor_cgroup_id helper")

Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---

diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 32c553556bbd..e03a92430383 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -567,20 +567,11 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp,
 static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
 					     int ancestor_level)
 {
-	struct cgroup *ptr;
-
 	if (cgrp->level < ancestor_level)
 		return NULL;
-
-	for (ptr = cgrp;
-	     ptr && ptr->level > ancestor_level;
-	     ptr = cgroup_parent(ptr))
-		;
-
-	if (ptr && ptr->level == ancestor_level)
-		return ptr;
-
-	return NULL;
+	while (cgrp && cgrp->level > ancestor_level)
+		cgrp = cgroup_parent(cgrp);
+	return cgrp;
 }
 
 /**