[SK_BUFF]: Convert skb->tail to sk_buff_data_t

So that it is also an offset from skb->head, reduces its size from 8 to 4 bytes
on 64bit architectures, allowing us to combine the 4 bytes hole left by the
layer headers conversion, reducing struct sk_buff size to 256 bytes, i.e. 4
64byte cachelines, and since the sk_buff slab cache is SLAB_HWCACHE_ALIGN...
:-)

Many calculations that previously required that skb->{transport,network,
mac}_header be first converted to a pointer now can be done directly, being
meaningful as offsets or pointers.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 2 deletions

diff --git a/net/core/wireless.c b/net/core/wireless.c
index 7c6a5db544f1..4a777b68e3bc 100644
--- a/net/core/wireless.c
+++ b/net/core/wireless.c
@@ -1938,7 +1938,7 @@ static inline int rtnetlink_fill_iwinfo(struct sk_buff *	skb,
 {
         struct ifinfomsg *r;
         struct nlmsghdr  *nlh;
-        unsigned char    *b = skb->tail;
+        unsigned char    *b = skb_tail_pointer(skb);
 
         nlh = NLMSG_PUT(skb, 0, 0, type, sizeof(*r));
         r = NLMSG_DATA(nlh);
@@ -1952,7 +1952,7 @@ static inline int rtnetlink_fill_iwinfo(struct sk_buff *	skb,
         /* Add the wireless events in the netlink packet */
         RTA_PUT(skb, IFLA_WIRELESS, event_len, event);
 
-        nlh->nlmsg_len = skb->tail - b;
+        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
         return skb->len;
 
 nlmsg_failure: