[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/sched/act_ipt.c b/net/sched/act_ipt.c
index 47f0b1324239..2ccfd5b20fab 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -245,7 +245,7 @@ static int tcf_ipt(struct sk_buff *skb, struct tc_action *a,
 
 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 {
-        unsigned char *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct tcf_ipt *ipt = a->priv;
         struct ipt_entry_target *t;
         struct tcf_t tm;