[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/irda/ircomm/ircomm_param.c b/net/irda/ircomm/ircomm_param.c
index 01d7c9c7b3b4..e5e4792a0314 100644
--- a/net/irda/ircomm/ircomm_param.c
+++ b/net/irda/ircomm/ircomm_param.c
@@ -133,8 +133,8 @@ int ircomm_param_request(struct ircomm_tty_cb *self, __u8 pi, int flush)
          * Inserting is a little bit tricky since we don't know how much
          * room we will need. But this should hopefully work OK
          */
-        count = irda_param_insert(self, pi, skb->tail, skb_tailroom(skb),
-                                  &ircomm_param_info);
+        count = irda_param_insert(self, pi, skb_tail_pointer(skb),
+                                  skb_tailroom(skb), &ircomm_param_info);
         if (count < 0) {
                 IRDA_WARNING("%s(), no room for parameter!\n", __FUNCTION__);
                 spin_unlock_irqrestore(&self->spinlock, flags);