[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, 10 insertions, 10 deletions

diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index d83414d828d8..be98a01253e9 100644
--- a/net/sched/sch_cbq.c
+++ b/net/sched/sch_cbq.c
@@ -1465,7 +1465,7 @@ static int cbq_init(struct Qdisc *sch, struct rtattr *opt)
 
 static __inline__ int cbq_dump_rate(struct sk_buff *skb, struct cbq_class *cl)
 {
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
 
         RTA_PUT(skb, TCA_CBQ_RATE, sizeof(cl->R_tab->rate), &cl->R_tab->rate);
         return skb->len;
@@ -1477,7 +1477,7 @@ rtattr_failure:
 
 static __inline__ int cbq_dump_lss(struct sk_buff *skb, struct cbq_class *cl)
 {
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct tc_cbq_lssopt opt;
 
         opt.flags = 0;
@@ -1502,7 +1502,7 @@ rtattr_failure:
 
 static __inline__ int cbq_dump_wrr(struct sk_buff *skb, struct cbq_class *cl)
 {
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct tc_cbq_wrropt opt;
 
         opt.flags = 0;
@@ -1520,7 +1520,7 @@ rtattr_failure:
 
 static __inline__ int cbq_dump_ovl(struct sk_buff *skb, struct cbq_class *cl)
 {
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct tc_cbq_ovl opt;
 
         opt.strategy = cl->ovl_strategy;
@@ -1537,7 +1537,7 @@ rtattr_failure:
 
 static __inline__ int cbq_dump_fopt(struct sk_buff *skb, struct cbq_class *cl)
 {
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct tc_cbq_fopt opt;
 
         if (cl->split || cl->defmap) {
@@ -1556,7 +1556,7 @@ rtattr_failure:
 #ifdef CONFIG_NET_CLS_POLICE
 static __inline__ int cbq_dump_police(struct sk_buff *skb, struct cbq_class *cl)
 {
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct tc_cbq_police opt;
 
         if (cl->police) {
@@ -1590,14 +1590,14 @@ static int cbq_dump_attr(struct sk_buff *skb, struct cbq_class *cl)
 static int cbq_dump(struct Qdisc *sch, struct sk_buff *skb)
 {
         struct cbq_sched_data *q = qdisc_priv(sch);
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct rtattr *rta;
 
         rta = (struct rtattr*)b;
         RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
         if (cbq_dump_attr(skb, &q->link) < 0)
                 goto rtattr_failure;
-        rta->rta_len = skb->tail - b;
+        rta->rta_len = skb_tail_pointer(skb) - b;
         return skb->len;
 
 rtattr_failure:
@@ -1619,7 +1619,7 @@ cbq_dump_class(struct Qdisc *sch, unsigned long arg,
                struct sk_buff *skb, struct tcmsg *tcm)
 {
         struct cbq_class *cl = (struct cbq_class*)arg;
-        unsigned char    *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct rtattr *rta;
 
         if (cl->tparent)
@@ -1633,7 +1633,7 @@ cbq_dump_class(struct Qdisc *sch, unsigned long arg,
         RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
         if (cbq_dump_attr(skb, cl) < 0)
                 goto rtattr_failure;
-        rta->rta_len = skb->tail - b;
+        rta->rta_len = skb_tail_pointer(skb) - b;
         return skb->len;
 
 rtattr_failure: