[SK_BUFF]: Introduce skb_reset_network_header(skb)

For the common, open coded 'skb->nh.raw = skb->data' operation, so that we can
later turn skb->nh.raw into a offset, reducing the size of struct sk_buff in
64bit land while possibly keeping it as a pointer on 32bit.

This one touches just the most simple case, next will handle the slightly more
"complex" cases.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/decnet/dn_dev.c b/net/decnet/dn_dev.c
index 060d725..95871a6 100644
--- a/net/decnet/dn_dev.c
+++ b/net/decnet/dn_dev.c
@@ -913,7 +913,7 @@
 	pktlen = (__le16 *)skb_push(skb,2);
 	*pktlen = dn_htons(skb->len - 2);
 
-	skb->nh.raw = skb->data;
+	skb_reset_network_header(skb);
 
 	dn_rt_finish_output(skb, dn_rt_all_rt_mcast, msg->id);
 }
@@ -1005,7 +1005,7 @@
 	pktlen = (__le16 *)skb_push(skb, 2);
 	*pktlen = dn_htons(skb->len - 2);
 
-	skb->nh.raw = skb->data;
+	skb_reset_network_header(skb);
 
 	if (dn_am_i_a_router(dn, dn_db, ifa)) {
 		struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
diff --git a/net/decnet/dn_neigh.c b/net/decnet/dn_neigh.c
index bf701cf..4bf066c 100644
--- a/net/decnet/dn_neigh.c
+++ b/net/decnet/dn_neigh.c
@@ -261,7 +261,7 @@
 	lp->s_class  = 0;
 	lp->pt       = 0;
 
-	skb->nh.raw = skb->data;
+	skb_reset_network_header(skb);
 
 	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 }
@@ -300,7 +300,7 @@
 	sp->srcnode    = cb->src;
 	sp->forward    = cb->hops & 0x3f;
 
-	skb->nh.raw = skb->data;
+	skb_reset_network_header(skb);
 
 	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 }
@@ -342,7 +342,7 @@
 	sp->srcnode  = cb->src & dn_htons(0x03ff);
 	sp->forward  = cb->hops & 0x3f;
 
-	skb->nh.raw = skb->data;
+	skb_reset_network_header(skb);
 
 	return NF_HOOK(PF_DECnet, NF_DN_POST_ROUTING, skb, NULL, neigh->dev, dn_neigh_output_packet);
 }
diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index ef94ca5..34079b7 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -615,7 +615,7 @@
 		flags = *skb->data;
 	}
 
-	skb->nh.raw = skb->data;
+	skb_reset_network_header(skb);
 
 	/*
 	 * Weed out future version DECnet