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/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index e185961..6c2d615 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -918,7 +918,7 @@
 	UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
 
 	/* Something worked... */
-	dst_confirm(skb->dst);
+	dst_confirm(skb_dst(skb));
 
 	xprt_adjust_cwnd(task, copied);
 	xprt_update_rtt(task);