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/inet_hashtables.h b/include/net/inet_hashtables.h
index a44e224..d522dcf 100644
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
@@ -385,7 +385,7 @@
 	if (unlikely(sk = skb_steal_sock(skb)))
 		return sk;
 	else
-		return __inet_lookup(dev_net(skb->dst->dev), hashinfo,
+		return __inet_lookup(dev_net(skb_dst(skb)->dev), hashinfo,
 				     iph->saddr, sport,
 				     iph->daddr, dport, inet_iif(skb));
 }