static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
			      struct sk_buff *skb, u32 mtu,
			      bool confirm_neigh)
{
	struct rtable *rt = (struct rtable *) dst;
	struct flowi4 fl4;

	ip_rt_build_flow_key(&fl4, sk, skb);

	/* Don't make lookup fail for bridged encapsulations */
	if (skb && netif_is_any_bridge_port(skb->dev))
		fl4.flowi4_oif = 0;

	__ip_rt_update_pmtu(rt, &fl4, mtu);
}
static void ip_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
			      struct sk_buff *skb, u32 mtu,
			      bool confirm_neigh)
{
	struct rtable *rt = (struct rtable *) dst;
	struct flowi4 fl4;

	ip_rt_build_flow_key(&fl4, sk, skb);

	 
	if (skb && netif_is_any_bridge_port(skb->dev))
		fl4.flowi4_oif = 0;

	__ip_rt_update_pmtu(rt, &fl4, mtu);
}