[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/drivers/isdn/i4l/isdn_net.c b/drivers/isdn/i4l/isdn_net.c
index cd3b1fa4a414..aa83277aba74 100644
--- a/drivers/isdn/i4l/isdn_net.c
+++ b/drivers/isdn/i4l/isdn_net.c
@@ -881,7 +881,7 @@ isdn_net_log_skb(struct sk_buff * skb, isdn_net_local * lp)
 
         addinfo[0] = '\0';
         /* This check stolen from 2.1.72 dev_queue_xmit_nit() */
-        if (p < skb->data || p >= skb->tail) {
+        if (p < skb->data || skb->network_header >= skb->tail) {
                 /* fall back to old isdn_net_log_packet method() */
                 char * buf = skb->data;