void ipv6_sock_mc_close(struct sock *sk)
{
	struct ipv6_pinfo *np = inet6_sk(sk);

	if (!rcu_access_pointer(np->ipv6_mc_list))
		return;

	rtnl_lock();
	lock_sock(sk);
	__ipv6_sock_mc_close(sk);
	release_sock(sk);
	rtnl_unlock();
}
void ipv6_sock_mc_close(struct sock *sk)
{
	struct ipv6_pinfo *np = inet6_sk(sk);

	if (!rcu_access_pointer(np->ipv6_mc_list))
		return;

	rtnl_lock();
	lock_sock(sk);
	__ipv6_sock_mc_close(sk);
	release_sock(sk);
	rtnl_unlock();
}