act_nat: use stack variable

{

	unsigned char *b = skb_tail_pointer(skb);

	struct tcf_nat *p = a->priv;

	struct tc_nat *opt;

	struct tc_nat opt;

	struct tcf_t t;

	int s;

	s = sizeof(*opt);

	opt.old_addr = p->old_addr;

	opt.new_addr = p->new_addr;

	opt.mask = p->mask;

	opt.flags = p->flags;

	/* netlink spinlocks held above us - must use ATOMIC */

	opt = kzalloc(s, GFP_ATOMIC);

	if (unlikely(!opt))

		return -ENOBUFS;

	opt.index = p->tcf_index;

	opt.action = p->tcf_action;

	opt.refcnt = p->tcf_refcnt - ref;

	opt.bindcnt = p->tcf_bindcnt - bind;

	opt->old_addr = p->old_addr;

	opt->new_addr = p->new_addr;

	opt->mask = p->mask;

	opt->flags = p->flags;

	opt->index = p->tcf_index;

	opt->action = p->tcf_action;

	opt->refcnt = p->tcf_refcnt - ref;

	opt->bindcnt = p->tcf_bindcnt - bind;

	NLA_PUT(skb, TCA_NAT_PARMS, s, opt);

	NLA_PUT(skb, TCA_NAT_PARMS, sizeof(opt), &opt);

	t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);

	t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);

	t.expires = jiffies_to_clock_t(p->tcf_tm.expires);

	NLA_PUT(skb, TCA_NAT_TM, sizeof(t), &t);

	kfree(opt);

	return skb->len;

nla_put_failure:

	nlmsg_trim(skb, b);

	kfree(opt);

	return -1;

}