[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>
diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
index abc47cc..1f94df3 100644
--- a/net/sched/cls_route.c
+++ b/net/sched/cls_route.c
@@ -562,7 +562,7 @@
struct sk_buff *skb, struct tcmsg *t)
{
struct route4_filter *f = (struct route4_filter*)fh;
- unsigned char *b = skb->tail;
+ unsigned char *b = skb_tail_pointer(skb);
struct rtattr *rta;
u32 id;
@@ -591,7 +591,7 @@
if (tcf_exts_dump(skb, &f->exts, &route_ext_map) < 0)
goto rtattr_failure;
- rta->rta_len = skb->tail - b;
+ rta->rta_len = skb_tail_pointer(skb) - b;
if (tcf_exts_dump_stats(skb, &f->exts, &route_ext_map) < 0)
goto rtattr_failure;