net: skb->dst accessors

Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h
index f74665d..22c73a7 100644
--- a/include/net/inet6_hashtables.h
+++ b/include/net/inet6_hashtables.h
@@ -100,7 +100,7 @@
 
 	if (unlikely(sk = skb_steal_sock(skb)))
 		return sk;
-	else return __inet6_lookup(dev_net(skb->dst->dev), hashinfo,
+	else return __inet6_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
 				   &ipv6_hdr(skb)->saddr, sport,
 				   &ipv6_hdr(skb)->daddr, ntohs(dport),
 				   inet6_iif(skb));