[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/sch_atm.c b/net/sched/sch_atm.c
index baca874..1d7bb16 100644
--- a/net/sched/sch_atm.c
+++ b/net/sched/sch_atm.c
@@ -631,7 +631,7 @@
{
struct atm_qdisc_data *p = PRIV(sch);
struct atm_flow_data *flow = (struct atm_flow_data *) cl;
- unsigned char *b = skb->tail;
+ unsigned char *b = skb_tail_pointer(skb);
struct rtattr *rta;
DPRINTK("atm_tc_dump_class(sch %p,[qdisc %p],flow %p,skb %p,tcm %p)\n",
@@ -661,7 +661,7 @@
RTA_PUT(skb,TCA_ATM_EXCESS,sizeof(zero),&zero);
}
- rta->rta_len = skb->tail-b;
+ rta->rta_len = skb_tail_pointer(skb) - b;
return skb->len;
rtattr_failure: