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/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index 05b5aa0..923786b 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -204,7 +204,7 @@
 
 static int dn_neigh_output_packet(struct sk_buff *skb)
 {
-	struct dst_entry *dst = skb->dst;
+	struct dst_entry *dst = skb_dst(skb);
 	struct dn_route *rt = (struct dn_route *)dst;
 	struct neighbour *neigh = dst->neighbour;
 	struct net_device *dev = neigh->dev;
@@ -224,7 +224,7 @@
 
 static int dn_long_output(struct sk_buff *skb)
 {
-	struct dst_entry *dst = skb->dst;
+	struct dst_entry *dst = skb_dst(skb);
 	struct neighbour *neigh = dst->neighbour;
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_long_packet) + 3;
@@ -270,7 +270,7 @@
 
 static int dn_short_output(struct sk_buff *skb)
 {
-	struct dst_entry *dst = skb->dst;
+	struct dst_entry *dst = skb_dst(skb);
 	struct neighbour *neigh = dst->neighbour;
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;
@@ -313,7 +313,7 @@
  */
 static int dn_phase3_output(struct sk_buff *skb)
 {
-	struct dst_entry *dst = skb->dst;
+	struct dst_entry *dst = skb_dst(skb);
 	struct neighbour *neigh = dst->neighbour;
 	struct net_device *dev = neigh->dev;
 	int headroom = dev->hard_header_len + sizeof(struct dn_short_packet) + 2;