[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_htb.c b/net/sched/sch_htb.c
index f76c20c..c687388 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1110,7 +1110,7 @@
static int htb_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct htb_sched *q = qdisc_priv(sch);
- unsigned char *b = skb->tail;
+ unsigned char *b = skb_tail_pointer(skb);
struct rtattr *rta;
struct tc_htb_glob gopt;
spin_lock_bh(&sch->dev->queue_lock);
@@ -1123,12 +1123,12 @@
rta = (struct rtattr *)b;
RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
RTA_PUT(skb, TCA_HTB_INIT, sizeof(gopt), &gopt);
- rta->rta_len = skb->tail - b;
+ rta->rta_len = skb_tail_pointer(skb) - b;
spin_unlock_bh(&sch->dev->queue_lock);
return skb->len;
rtattr_failure:
spin_unlock_bh(&sch->dev->queue_lock);
- skb_trim(skb, skb->tail - skb->data);
+ skb_trim(skb, skb_tail_pointer(skb) - skb->data);
return -1;
}
@@ -1136,7 +1136,7 @@
struct sk_buff *skb, struct tcmsg *tcm)
{
struct htb_class *cl = (struct htb_class *)arg;
- unsigned char *b = skb->tail;
+ unsigned char *b = skb_tail_pointer(skb);
struct rtattr *rta;
struct tc_htb_opt opt;
@@ -1159,7 +1159,7 @@
opt.prio = cl->un.leaf.prio;
opt.level = cl->level;
RTA_PUT(skb, TCA_HTB_PARMS, sizeof(opt), &opt);
- rta->rta_len = skb->tail - b;
+ rta->rta_len = skb_tail_pointer(skb) - b;
spin_unlock_bh(&sch->dev->queue_lock);
return skb->len;
rtattr_failure: