---

yaml --- r: 350317 b: refs/heads/master c: 12a9d2f h: refs/heads/master i: 350315: 5443e6b v: v3
git-mirror · Jan 7, 2013 · 1ea14b2 · 1ea14b2
1 parent c92b6e6
commit 1ea14b2
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Showing 3 changed files with 28 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d5b1fe68baa7213f198e5be8cd1a1037258ab2c8
+refs/heads/master: 12a9d2fef1d35770d3cdc2cd1faabb83c45bc0fa
diff --git a/trunk/include/linux/cgroup.h b/trunk/include/linux/cgroup.h
@@ -558,6 +558,7 @@ static inline struct cgroup* task_cgroup(struct task_struct *task,
 
 struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
 					  struct cgroup *cgroup);
+struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos);
 
 /**
  * cgroup_for_each_descendant_pre - pre-order walk of a cgroup's descendants

diff --git a/trunk/kernel/cgroup.c b/trunk/kernel/cgroup.c
@@ -3017,6 +3017,32 @@ struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
 }
 EXPORT_SYMBOL_GPL(cgroup_next_descendant_pre);
 
+/**
+ * cgroup_rightmost_descendant - return the rightmost descendant of a cgroup
+ * @pos: cgroup of interest
+ *
+ * Return the rightmost descendant of @pos.  If there's no descendant,
+ * @pos is returned.  This can be used during pre-order traversal to skip
+ * subtree of @pos.
+ */
+struct cgroup *cgroup_rightmost_descendant(struct cgroup *pos)
+{
+	struct cgroup *last, *tmp;
+
+	WARN_ON_ONCE(!rcu_read_lock_held());
+
+	do {
+		last = pos;
+		/* ->prev isn't RCU safe, walk ->next till the end */
+		pos = NULL;
+		list_for_each_entry_rcu(tmp, &last->children, sibling)
+			pos = tmp;
+	} while (pos);
+
+	return last;
+}
+EXPORT_SYMBOL_GPL(cgroup_rightmost_descendant);
+
 static struct cgroup *cgroup_leftmost_descendant(struct cgroup *pos)
 {
 	struct cgroup *last;