Commit 58b79a91 authored Sep 06, 2013 by Tejun Heo

cgroup: fix cgroup post-order descendant walk of empty subtree



bd8815a6 ("cgroup: make css_for_each_descendant() and friends
include the origin css in the iteration") updated cgroup descendant
iterators to include the origin css; unfortuantely, it forgot to drop
special case handling in css_next_descendant_post() for empty subtree
leading to failure to visit the origin css without any child.

Fix it by dropping the special case handling and always returning the
leftmost descendant on the first iteration.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>

parent 26b0332e

kernel/cgroup.c

+3 −5

Original line number	Diff line number	Diff line
		@@ -3187,11 +3187,9 @@ css_next_descendant_post(struct cgroup_subsys_state *pos,

		WARN_ON_ONCE(!rcu_read_lock_held());

		/* if first iteration, visit the leftmost descendant */
		if (!pos) {
		next = css_leftmost_descendant(root);
		return next != root ? next : NULL;
		}
		/* if first iteration, visit leftmost descendant which may be @root */
		if (!pos)
		return css_leftmost_descendant(root);

		/* if we visited @root, we're done */
		if (pos == root)

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