int nft_register_expr(struct nft_expr_type *type)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	if (type->family == NFPROTO_UNSPEC)
		list_add_tail_rcu(&type->list, &nf_tables_expressions);
	else
		list_add_rcu(&type->list, &nf_tables_expressions);
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
	return 0;
}
int nft_register_expr(struct nft_expr_type *type)
{
	nfnl_lock(NFNL_SUBSYS_NFTABLES);
	if (type->family == NFPROTO_UNSPEC)
		list_add_tail_rcu(&type->list, &nf_tables_expressions);
	else
		list_add_rcu(&type->list, &nf_tables_expressions);
	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
	return 0;
}