ipv4: Inline neigh binding.

Get rid of all of the useless and costly indirection
by doing the neigh hash table lookup directly inside
of the neighbour binding.

Rename from arp_bind_neighbour to rt_bind_neighbour.

Use new helpers {__,}ipv4_neigh_lookup()

In rt_bind_neighbour() get rid of useless tests which
are never true in the context this function is called,
namely dev is never NULL and the dst->neighbour is
always NULL.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 32 insertions, 1 deletions

diff --git a/include/net/arp.h b/include/net/arp.h
index 723bde5..5e669e6f 100644
--- a/include/net/arp.h
+++ b/include/net/arp.h
@@ -15,6 +15,38 @@ 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 neigh_table *tbl, struct net_device *dev, u32 key)
+{
+	struct neigh_hash_table *nht;
+	struct neighbour *n;
+	u32 hash_val;
+
+	rcu_read_lock_bh();
+	nht = rcu_dereference_bh(tbl->nht);
+	hash_val = arp_hashfn(key, dev, nht->hash_rnd) >> (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;
+		}
+	}
+	rcu_read_unlock_bh();
+
+	return n;
+}
+
+static inline struct neighbour *ipv4_neigh_lookup(struct neigh_table *tbl, struct net_device *dev, const __be32 *pkey)
+{
+	struct neighbour *n = __ipv4_neigh_lookup(tbl, dev,
+						  *(__force u32 *)pkey);
+	if (n)
+		return n;
+	return neigh_create(tbl, pkey, dev);
+}
+
 extern void	arp_init(void);
 extern int	arp_find(unsigned char *haddr, struct sk_buff *skb);
 extern int	arp_ioctl(struct net *net, unsigned int cmd, void __user *arg);
@@ -22,7 +54,6 @@ extern void     arp_send(int type, int ptype, __be32 dest_ip,
 			 struct net_device *dev, __be32 src_ip,
 			 const unsigned char *dest_hw,
 			 const unsigned char *src_hw, const unsigned char *th);
-extern int	arp_bind_neighbour(struct dst_entry *dst);
 extern int	arp_mc_map(__be32 addr, u8 *haddr, struct net_device *dev, int dir);
 extern void	arp_ifdown(struct net_device *dev);