bridge: Cache net in br_nf_pre_routing_finish

This is prep work for passing net to the netfilter hooks.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/bridge/br_netfilter_hooks.c

@@ -346,6 +346,7 @@ static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb)
 {
 	struct net_device *dev = skb->dev;
 	struct iphdr *iph = ip_hdr(skb);
+	struct net *net = dev_net(dev);
 	struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 	struct rtable *rt;
 	int err;
@@ -371,7 +372,7 @@ static int br_nf_pre_routing_finish(struct sock *sk, struct sk_buff *skb)
 			if (err != -EHOSTUNREACH || !in_dev || IN_DEV_FORWARD(in_dev))
 				goto free_skb;
 
-			rt = ip_route_output(dev_net(dev), iph->daddr, 0,
+			rt = ip_route_output(net, iph->daddr, 0,
 					     RT_TOS(iph->tos), 0);
 			if (!IS_ERR(rt)) {
 				/* - Bridged-and-DNAT'ed traffic doesn't