[SK_BUFF]: Introduce skb_reset_transport_header(skb)

For the common, open coded 'skb->h.raw = skb->data' operation, so that we can
later turn skb->h.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 cases:

skb->h.raw = skb->data;
skb->h.raw = {skb_push|[__]skb_pull}()

The next ones 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/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 9c3c787..2dd32a2 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -101,7 +101,7 @@
 	if (hdr->version != 6)
 		goto err;
 
-	skb->h.raw = (u8 *)(hdr + 1);
+	skb->h.raw = skb->nh.raw + sizeof(*hdr);
 	IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
 
 	pkt_len = ntohs(hdr->payload_len);
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 1900c62..0f4434e 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -654,7 +654,7 @@
 			 * before previous one went down. */
 			if (frag) {
 				frag->ip_summed = CHECKSUM_NONE;
-				frag->h.raw = frag->data;
+				skb_reset_transport_header(frag);
 				fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
 				__skb_push(frag, hlen);
 				skb_reset_network_header(frag);
@@ -747,8 +747,8 @@
 		skb_reserve(frag, LL_RESERVED_SPACE(rt->u.dst.dev));
 		skb_put(frag, len + hlen + sizeof(struct frag_hdr));
 		skb_reset_network_header(frag);
-		fh = (struct frag_hdr*)(frag->data + hlen);
-		frag->h.raw = frag->data + hlen + sizeof(struct frag_hdr);
+		fh = (struct frag_hdr *)(skb_network_header(frag) + hlen);
+		frag->h.raw = frag->nh.raw + hlen + sizeof(struct frag_hdr);
 
 		/*
 		 *	Charge the memory for the fragment to any owner
@@ -991,7 +991,7 @@
 		skb_reset_network_header(skb);
 
 		/* initialize protocol header pointer */
-		skb->h.raw = skb->data + fragheaderlen;
+		skb->h.raw = skb->nh.raw + fragheaderlen;
 
 		skb->ip_summed = CHECKSUM_PARTIAL;
 		skb->csum = 0;
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index d16e0fd..da930fa 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -108,7 +108,7 @@
 	rcu_read_lock();
 	ops = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
 	if (likely(ops && ops->gso_send_check)) {
-		skb->h.raw = skb->data;
+		skb_reset_transport_header(skb);
 		err = ops->gso_send_check(skb);
 	}
 	rcu_read_unlock();
@@ -144,7 +144,7 @@
 	rcu_read_lock();
 	ops = ipv6_gso_pull_exthdrs(skb, ipv6h->nexthdr);
 	if (likely(ops && ops->gso_segment)) {
-		skb->h.raw = skb->data;
+		skb_reset_transport_header(skb);
 		segs = ops->gso_segment(skb, features);
 	}
 	rcu_read_unlock();
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index d3fbb1f..75138cf 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -634,7 +634,7 @@
 	head->nh.raw += sizeof(struct frag_hdr);
 
 	skb_shinfo(head)->frag_list = head->next;
-	head->h.raw = head->data;
+	skb_reset_transport_header(head);
 	skb_push(head, head->data - skb_network_header(head));
 	atomic_sub(head->truesize, &nf_ct_frag6_mem);
 
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index 156a37f..2594f0f 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -653,7 +653,7 @@
 	head->nh.raw += sizeof(struct frag_hdr);
 
 	skb_shinfo(head)->frag_list = head->next;
-	head->h.raw = head->data;
+	skb_reset_transport_header(head);
 	skb_push(head, head->data - skb_network_header(head));
 	atomic_sub(head->truesize, &ip6_frag_mem);
 
diff --git a/net/ipv6/xfrm6_mode_transport.c b/net/ipv6/xfrm6_mode_transport.c
index 358b60d..cae6cac 100644
--- a/net/ipv6/xfrm6_mode_transport.c
+++ b/net/ipv6/xfrm6_mode_transport.c
@@ -59,7 +59,7 @@
 	}
 	ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
 					   sizeof(struct ipv6hdr));
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 	return 0;
 }