[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, 3 insertions, 3 deletions

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 695b34051b9f..fa11bb750049 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -213,7 +213,7 @@ check_terminal:
                         off2 = 0;
                 }
 
-                if (ptr < skb->tail)
+                if (ptr < skb_tail_pointer(skb))
                         goto next_ht;
         }
 
@@ -718,7 +718,7 @@ static int u32_dump(struct tcf_proto *tp, unsigned long fh,
                      struct sk_buff *skb, struct tcmsg *t)
 {
         struct tc_u_knode *n = (struct tc_u_knode*)fh;
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct rtattr *rta;
 
         if (n == NULL)
@@ -765,7 +765,7 @@ static int u32_dump(struct tcf_proto *tp, unsigned long fh,
 #endif
         }
 
-        rta->rta_len = skb->tail - b;
+        rta->rta_len = skb_tail_pointer(skb) - b;
         if (TC_U32_KEY(n->handle))
                 if (tcf_exts_dump_stats(skb, &n->exts, &u32_ext_map) < 0)
                         goto rtattr_failure;