ipv4: Make neigh lookups directly in output packet path.

Do not use the dst cached neigh, we'll be getting rid of that.

Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 2630900..6e9a266 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -170,6 +170,7 @@
 	struct net_device *dev = dst->dev;
 	unsigned int hh_len = LL_RESERVED_SPACE(dev);
 	struct neighbour *neigh;
+	u32 nexthop;
 
 	if (rt->rt_type == RTN_MULTICAST) {
 		IP_UPD_PO_STATS(dev_net(dev), IPSTATS_MIB_OUTMCAST, skb->len);
@@ -191,15 +192,18 @@
 		skb = skb2;
 	}
 
-	rcu_read_lock();
-	neigh = dst_get_neighbour_noref(dst);
+	rcu_read_lock_bh();
+	nexthop = rt->rt_gateway ? rt->rt_gateway : ip_hdr(skb)->daddr;
+	neigh = __ipv4_neigh_lookup_noref(dev, nexthop);
+	if (unlikely(!neigh))
+		neigh = __neigh_create(&arp_tbl, &nexthop, dev, false);
 	if (neigh) {
 		int res = neigh_output(neigh, skb);
 
-		rcu_read_unlock();
+		rcu_read_unlock_bh();
 		return res;
 	}
-	rcu_read_unlock();
+	rcu_read_unlock_bh();
 
 	net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
 			    __func__);