cgroup: separate out cgroup_has_live_children() from cgroup_destroy_locked()
We're expecting another user.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b57a949..3f5f481 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -3295,6 +3295,21 @@
return css_parent(pos);
}
+static bool cgroup_has_live_children(struct cgroup *cgrp)
+{
+ struct cgroup *child;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(child, &cgrp->children, sibling) {
+ if (!cgroup_is_dead(child)) {
+ rcu_read_unlock();
+ return true;
+ }
+ }
+ rcu_read_unlock();
+ return false;
+}
+
/**
* css_advance_task_iter - advance a task itererator to the next css_set
* @it: the iterator to advance
@@ -4465,7 +4480,6 @@
static int cgroup_destroy_locked(struct cgroup *cgrp)
__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
- struct cgroup *child;
struct cgroup_subsys_state *css;
bool empty;
int ssid;
@@ -4487,15 +4501,7 @@
* emptiness as dead children linger on it while being destroyed;
* otherwise, "rmdir parent/child parent" may fail with -EBUSY.
*/
- empty = true;
- rcu_read_lock();
- list_for_each_entry_rcu(child, &cgrp->children, sibling) {
- empty = cgroup_is_dead(child);
- if (!empty)
- break;
- }
- rcu_read_unlock();
- if (!empty)
+ if (cgroup_has_live_children(cgrp))
return -EBUSY;
/*
