current_cgns_cgroup_from_root(struct cgroup_root *root)
{
	struct cgroup *res = NULL;
	struct css_set *cset;

	lockdep_assert_held(&css_set_lock);

	rcu_read_lock();

	cset = current->nsproxy->cgroup_ns->root_cset;
	if (cset == &init_css_set) {
		res = &root->cgrp;
	} else if (root == &cgrp_dfl_root) {
		res = cset->dfl_cgrp;
	} else {
		struct cgrp_cset_link *link;

		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
			struct cgroup *c = link->cgrp;

			if (c->root == root) {
				res = c;
				break;
			}
		}
	}
	rcu_read_unlock();

	BUG_ON(!res);
	return res;
}
current_cgns_cgroup_from_root(struct cgroup_root *root)
{
	struct cgroup *res = NULL;
	struct css_set *cset;

	lockdep_assert_held(&css_set_lock);

	rcu_read_lock();

	cset = current->nsproxy->cgroup_ns->root_cset;
	if (cset == &init_css_set) {
		res = &root->cgrp;
	} else if (root == &cgrp_dfl_root) {
		res = cset->dfl_cgrp;
	} else {
		struct cgrp_cset_link *link;

		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
			struct cgroup *c = link->cgrp;

			if (c->root == root) {
				res = c;
				break;
			}
		}
	}
	rcu_read_unlock();

	BUG_ON(!res);
	return res;
}