[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, 1 insertions, 1 deletions

diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 8705f6a502d9..2b3be68b70a7 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -1077,7 +1077,7 @@ static int rawv6_ioctl(struct sock *sk, int cmd, unsigned long arg)
                         spin_lock_bh(&sk->sk_receive_queue.lock);
                         skb = skb_peek(&sk->sk_receive_queue);
                         if (skb != NULL)
-                                amount = skb->tail - skb_transport_header(skb);
+                                amount = skb->tail - skb->transport_header;
                         spin_unlock_bh(&sk->sk_receive_queue.lock);
                         return put_user(amount, (int __user *)arg);
                 }