@@ -568,7 +568,7 @@ struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
*
* If a subsystem synchronizes against the parent in its ->css_online() and
* before starting iterating, and synchronizes against @pos on each
- * iteration, any descendant cgroup which finished ->css_offline() is
+ * iteration, any descendant cgroup which finished ->css_online() is
* guaranteed to be visible in the future iterations.
*
* In other words, the following guarantees that a descendant can't escape
@@ -3001,11 +3001,8 @@ struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
WARN_ON_ONCE(!rcu_read_lock_held());
/* if first iteration, pretend we just visited @cgroup */
- if (!pos) {
- if (list_empty(&cgroup->children))
- return NULL;
+ if (!pos)
pos = cgroup;
- }
/* visit the first child if exists */
next = list_first_or_null_rcu(&pos->children, struct cgroup, sibling);
@@ -3013,14 +3010,14 @@ struct cgroup *cgroup_next_descendant_pre(struct cgroup *pos,
return next;
/* no child, visit my or the closest ancestor's next sibling */
- do {
+ while (pos != cgroup) {
next = list_entry_rcu(pos->sibling.next, struct cgroup,
sibling);
if (&next->sibling != &pos->parent->children)
return next;
pos = pos->parent;
- } while (pos != cgroup);
+ }
return NULL;
}