[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>

drivers/infiniband/hw/cxgb3/iwch_cm.c

@@ -507,7 +507,7 @@ static void send_mpa_req(struct iwch_ep *ep, struct sk_buff *skb)
 	 */
 	skb_get(skb);
 	set_arp_failure_handler(skb, arp_failure_discard);
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 	len = skb->len;
 	req = (struct tx_data_wr *) skb_push(skb, sizeof(*req));
 	req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA));
@@ -559,7 +559,7 @@ static int send_mpa_reject(struct iwch_ep *ep, const void *pdata, u8 plen)
 	skb_get(skb);
 	skb->priority = CPL_PRIORITY_DATA;
 	set_arp_failure_handler(skb, arp_failure_discard);
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 	req = (struct tx_data_wr *) skb_push(skb, sizeof(*req));
 	req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA));
 	req->wr_lo = htonl(V_WR_TID(ep->hwtid));
@@ -610,7 +610,7 @@ static int send_mpa_reply(struct iwch_ep *ep, const void *pdata, u8 plen)
 	 */
 	skb_get(skb);
 	set_arp_failure_handler(skb, arp_failure_discard);
-	skb->h.raw = skb->data;
+	skb_reset_transport_header(skb);
 	len = skb->len;
 	req = (struct tx_data_wr *) skb_push(skb, sizeof(*req));
 	req->wr_hi = htonl(V_WR_OP(FW_WROPCODE_OFLD_TX_DATA));