net: Embed hh_cache inside of struct neighbour.

Now that there is a one-to-one correspondance between neighbour
and hh_cache entries, we no longer need:

1) dynamic allocation
2) attachment to dst->hh
3) refcounting

Initialization of the hh_cache entry is indicated by hh_len
being non-zero, and such initialization is always done with
the neighbour's lock held as a writer.

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

1 files changed, 9 insertions, 5 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 9d4b165..f0f144c 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -100,6 +100,7 @@ static int ip6_finish_output2(struct sk_buff *skb)
 {
 	struct dst_entry *dst = skb_dst(skb);
 	struct net_device *dev = dst->dev;
+	struct neighbour *neigh;
 
 	skb->protocol = htons(ETH_P_IPV6);
 	skb->dev = dev;
@@ -134,11 +135,14 @@ static int ip6_finish_output2(struct sk_buff *skb)
 				skb->len);
 	}
 
-	if (dst->hh)
-		return neigh_hh_output(dst->hh, skb);
-	else if (dst->neighbour)
-		return dst->neighbour->output(skb);
-
+	neigh = dst->neighbour;
+	if (neigh) {
+		struct hh_cache *hh = &neigh->hh;
+		if (hh->hh_len)
+			return neigh_hh_output(hh, skb);
+		else
+			return dst->neighbour->output(skb);
+	}
 	IP6_INC_STATS_BH(dev_net(dst->dev),
 			 ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
 	kfree_skb(skb);