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>

1 files changed, 19 insertions, 9 deletions

diff --git a/include/net/arp.h b/include/net/arp.h
index 4a1f3fb562eb..4617d9841132 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -15,24 +15,34 @@ static inline u32 arp_hashfn(u32 key, const struct net_device *dev, u32 hash_rnd
 	return val * hash_rnd;
 }
 
-static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)
+static inline struct neighbour *__ipv4_neigh_lookup_noref(struct net_device *dev, u32 key)
 {
-	struct neigh_hash_table *nht;
+	struct neigh_hash_table *nht = rcu_dereference_bh(arp_tbl.nht);
 	struct neighbour *n;
 	u32 hash_val;
 
-	rcu_read_lock_bh();
-	nht = rcu_dereference_bh(arp_tbl.nht);
+	if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
+		key = 0;
+
 	hash_val = arp_hashfn(key, dev, nht->hash_rnd[0]) >> (32 - nht->hash_shift);
 	for (n = rcu_dereference_bh(nht->hash_buckets[hash_val]);
 	     n != NULL;
 	     n = rcu_dereference_bh(n->next)) {
-		if (n->dev == dev && *(u32 *)n->primary_key == key) {
-			if (!atomic_inc_not_zero(&n->refcnt))
-				n = NULL;
-			break;
-		}
+		if (n->dev == dev && *(u32 *)n->primary_key == key)
+			return n;
 	}
+
+	return NULL;
+}
+
+static inline struct neighbour *__ipv4_neigh_lookup(struct net_device *dev, u32 key)
+{
+	struct neighbour *n;
+
+	rcu_read_lock_bh();
+	n = __ipv4_neigh_lookup_noref(dev, key);
+	if (n && !atomic_inc_not_zero(&n->refcnt))
+		n = NULL;
 	rcu_read_unlock_bh();
 
 	return n;