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>

3 files changed, 59 insertions, 28 deletions

diff --git a/include/net/arp.h b/include/net/arp.h
index 723bde501c64..5e669e6ffb42 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);
 
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 4412b57f6ff6..3e5545675ccf 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -517,30 +517,6 @@ EXPORT_SYMBOL(arp_find);
 
 /* END OF OBSOLETE FUNCTIONS */
 
-int arp_bind_neighbour(struct dst_entry *dst)
-{
-        struct net_device *dev = dst->dev;
-        struct neighbour *n = dst->neighbour;
-
-        if (dev == NULL)
-                return -EINVAL;
-        if (n == NULL) {
-                __be32 nexthop = ((struct rtable *)dst)->rt_gateway;
-                if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
-                        nexthop = 0;
-                n = __neigh_lookup_errno(
-#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
-                                         dev->type == ARPHRD_ATM ?
-                                         clip_tbl_hook :
-#endif
-                                         &arp_tbl, &nexthop, dev);
-                if (IS_ERR(n))
-                        return PTR_ERR(n);
-                dst->neighbour = n;
-        }
-        return 0;
-}
-
 /*
  * Check if we can use proxy ARP for this path
  */
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a8ccd9bca09c..c6388e825ed3 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -108,6 +108,7 @@
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
 #endif
+#include <net/atmclip.h>
 
 #define RT_FL_TOS(oldflp4) \
     ((u32)(oldflp4->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK)))
@@ -1006,6 +1007,29 @@ static int slow_chain_length(const struct rtable *head)
         return length >> FRACT_BITS;
 }
 
+static int rt_bind_neighbour(struct rtable *rt)
+{
+        static const __be32 inaddr_any = 0;
+        struct net_device *dev = rt->dst.dev;
+        struct neigh_table *tbl = &arp_tbl;
+        const __be32 *nexthop;
+        struct neighbour *n;
+
+#if defined(CONFIG_ATM_CLIP) || defined(CONFIG_ATM_CLIP_MODULE)
+        if (dev->type == ARPHRD_ATM)
+                tbl = clip_tbl_hook;
+#endif
+        nexthop = &rt->rt_gateway;
+        if (dev->flags & (IFF_LOOPBACK | IFF_POINTOPOINT))
+                nexthop = &inaddr_any;
+        n = ipv4_neigh_lookup(tbl, dev, nexthop);
+        if (IS_ERR(n))
+                return PTR_ERR(n);
+        rt->dst.neighbour = n;
+
+        return 0;
+}
+
 static struct rtable *rt_intern_hash(unsigned hash, struct rtable *rt,
                                      struct sk_buff *skb, int ifindex)
 {
@@ -1042,7 +1066,7 @@ restart:
 
                 rt->dst.flags |= DST_NOCACHE;
                 if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
-                        int err = arp_bind_neighbour(&rt->dst);
+                        int err = rt_bind_neighbour(rt);
                         if (err) {
                                 if (net_ratelimit())
                                         printk(KERN_WARNING
@@ -1138,7 +1162,7 @@ restart:
            route or unicast forwarding path.
          */
         if (rt->rt_type == RTN_UNICAST || rt_is_output_route(rt)) {
-                int err = arp_bind_neighbour(&rt->dst);
+                int err = rt_bind_neighbour(rt);
                 if (err) {
                         spin_unlock_bh(rt_hash_lock_addr(hash));
 
@@ -1599,7 +1623,7 @@ static int check_peer_redir(struct dst_entry *dst, struct inet_peer *peer)
         rt->dst.neighbour = NULL;
 
         rt->rt_gateway = peer->redirect_learned.a4;
-        if (arp_bind_neighbour(&rt->dst) ||
+        if (rt_bind_neighbour(rt) ||
             !(rt->dst.neighbour->nud_state & NUD_VALID)) {
                 if (rt->dst.neighbour)
                         neigh_event_send(rt->dst.neighbour, NULL);