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, 6 insertions, 0 deletions

diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index f123c6c..ee7d1ce 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -93,12 +93,18 @@ static u32 dn_neigh_hash(const void *pkey,
 	return jhash_2words(*(__u16 *)pkey, 0, hash_rnd[0]);
 }
 
+static bool dn_key_eq(const struct neighbour *neigh, const void *pkey)
+{
+	return neigh_key_eq16(neigh, pkey);
+}
+
 struct neigh_table dn_neigh_table = {
 	.family =			PF_DECnet,
 	.entry_size =			NEIGH_ENTRY_SIZE(sizeof(struct dn_neigh)),
 	.key_len =			sizeof(__le16),
 	.protocol =			cpu_to_be16(ETH_P_DNA_RT),
 	.hash =				dn_neigh_hash,
+	.key_eq =			dn_key_eq,
 	.constructor =			dn_neigh_construct,
 	.id =				"dn_neigh_cache",
 	.parms ={