neigh: Factor out ___neigh_lookup_noref

While looking at the mpls code I found myself writing yet another
version of neigh_lookup_noref.  We currently have __ipv4_lookup_noref
and __ipv6_lookup_noref.

So to make my work a little easier and to make it a smidge easier to
verify/maintain the mpls code in the future I stopped and wrote
___neigh_lookup_noref.  Then I rewote __ipv4_lookup_noref and
__ipv6_lookup_noref in terms of this new function.  I tested my new
version by verifying that the same code is generated in
ip_finish_output2 and ip6_finish_output2 where these functions are
inlined.

To get to ___neigh_lookup_noref I added a new neighbour cache table
function key_eq.  So that the static size of the key would be
available.

I also added __neigh_lookup_noref for people who want to to lookup
a neighbour table entry quickly but don't know which neibhgour table
they are going to look up.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 18 deletions

diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 6bbda34d5e59..b3a7751251b4 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -156,24 +156,7 @@ static inline u32 ndisc_hashfn(const void *pkey, const struct net_device *dev, _
 
 static inline struct neighbour *__ipv6_neigh_lookup_noref(struct net_device *dev, const void *pkey)
 {
-	struct neigh_hash_table *nht;
-	const u32 *p32 = pkey;
-	struct neighbour *n;
-	u32 hash_val;
-
-	nht = rcu_dereference_bh(nd_tbl.nht);
-	hash_val = ndisc_hashfn(pkey, 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)) {
-		u32 *n32 = (u32 *) n->primary_key;
-		if (n->dev == dev &&
-		    ((n32[0] ^ p32[0]) | (n32[1] ^ p32[1]) |
-		     (n32[2] ^ p32[2]) | (n32[3] ^ p32[3])) == 0)
-			return n;
-	}
-
-	return NULL;
+	return ___neigh_lookup_noref(&nd_tbl, neigh_key_eq128, ndisc_hashfn, pkey, dev);
 }
 
 static inline struct neighbour *__ipv6_neigh_lookup(struct net_device *dev, const void *pkey)