[SK_BUFF]: Introduce skb_reset_mac_header(skb)

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

2 files changed, 7 insertions, 2 deletions

diff --git a/include/linux/hdlc.h b/include/linux/hdlc.h
index d4b333938f73..0fe562af9c8c 100644
--- a/include/linux/hdlc.h
+++ b/include/linux/hdlc.h
@@ -132,8 +132,8 @@ static __inline__ __be16 hdlc_type_trans(struct sk_buff *skb,
 {
         hdlc_device *hdlc = dev_to_hdlc(dev);
 
-        skb->mac.raw  = skb->data;
-        skb->dev      = dev;
+        skb->dev = dev;
+        skb_reset_mac_header(skb);
 
         if (hdlc->proto->type_trans)
                 return hdlc->proto->type_trans(skb, dev);
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index df229bd5f1a9..748f254b50cc 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -960,6 +960,11 @@ static inline void skb_reserve(struct sk_buff *skb, int len)
         skb->tail += len;
 }
 
+static inline void skb_reset_mac_header(struct sk_buff *skb)
+{
+        skb->mac.raw = skb->data;
+}
+
 /*
  * CPUs often take a performance hit when accessing unaligned memory
  * locations. The actual performance hit varies, it can be small if the