[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, 26 insertions, 26 deletions

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index cb21617a5670..28326fb1fc4e 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -93,7 +93,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
                                 continue;
                         a->priv = p;
                         a->order = n_i;
-                        r = (struct rtattr*) skb->tail;
+                        r = (struct rtattr *)skb_tail_pointer(skb);
                         RTA_PUT(skb, a->order, 0, NULL);
                         err = tcf_action_dump_1(skb, a, 0, 0);
                         if (err < 0) {
@@ -101,7 +101,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb,
                                 skb_trim(skb, (u8*)r - skb->data);
                                 goto done;
                         }
-                        r->rta_len = skb->tail - (u8*)r;
+                        r->rta_len = skb_tail_pointer(skb) - (u8 *)r;
                         n_i++;
                         if (n_i >= TCA_ACT_MAX_PRIO)
                                 goto done;
@@ -125,7 +125,7 @@ static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a,
         struct rtattr *r ;
         int i= 0, n_i = 0;
 
-        r = (struct rtattr*) skb->tail;
+        r = (struct rtattr *)skb_tail_pointer(skb);
         RTA_PUT(skb, a->order, 0, NULL);
         RTA_PUT(skb, TCA_KIND, IFNAMSIZ, a->ops->kind);
         for (i = 0; i < (hinfo->hmask + 1); i++) {
@@ -140,7 +140,7 @@ static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a,
                 }
         }
         RTA_PUT(skb, TCA_FCNT, 4, &n_i);
-        r->rta_len = skb->tail - (u8*)r;
+        r->rta_len = skb_tail_pointer(skb) - (u8 *)r;
 
         return n_i;
 rtattr_failure:
@@ -423,7 +423,7 @@ int
 tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
 {
         int err = -EINVAL;
-        unsigned char *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct rtattr *r;
 
         if (a->ops == NULL || a->ops->dump == NULL)
@@ -432,10 +432,10 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref)
         RTA_PUT(skb, TCA_KIND, IFNAMSIZ, a->ops->kind);
         if (tcf_action_copy_stats(skb, a, 0))
                 goto rtattr_failure;
-        r = (struct rtattr*) skb->tail;
+        r = (struct rtattr *)skb_tail_pointer(skb);
         RTA_PUT(skb, TCA_OPTIONS, 0, NULL);
         if ((err = tcf_action_dump_old(skb, a, bind, ref)) > 0) {
-                r->rta_len = skb->tail - (u8*)r;
+                r->rta_len = skb_tail_pointer(skb) - (u8 *)r;
                 return err;
         }
 
@@ -449,17 +449,17 @@ tcf_action_dump(struct sk_buff *skb, struct tc_action *act, int bind, int ref)
 {
         struct tc_action *a;
         int err = -EINVAL;
-        unsigned char *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct rtattr *r ;
 
         while ((a = act) != NULL) {
-                r = (struct rtattr*) skb->tail;
+                r = (struct rtattr *)skb_tail_pointer(skb);
                 act = a->next;
                 RTA_PUT(skb, a->order, 0, NULL);
                 err = tcf_action_dump_1(skb, a, bind, ref);
                 if (err < 0)
                         goto errout;
-                r->rta_len = skb->tail - (u8*)r;
+                r->rta_len = skb_tail_pointer(skb) - (u8 *)r;
         }
 
         return 0;
@@ -635,7 +635,7 @@ tca_get_fill(struct sk_buff *skb, struct tc_action *a, u32 pid, u32 seq,
 {
         struct tcamsg *t;
         struct nlmsghdr *nlh;
-        unsigned char *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct rtattr *x;
 
         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*t), flags);
@@ -645,15 +645,15 @@ tca_get_fill(struct sk_buff *skb, struct tc_action *a, u32 pid, u32 seq,
         t->tca__pad1 = 0;
         t->tca__pad2 = 0;
 
-        x = (struct rtattr*) skb->tail;
+        x = (struct rtattr *)skb_tail_pointer(skb);
         RTA_PUT(skb, TCA_ACT_TAB, 0, NULL);
 
         if (tcf_action_dump(skb, a, bind, ref) < 0)
                 goto rtattr_failure;
 
-        x->rta_len = skb->tail - (u8*)x;
+        x->rta_len = skb_tail_pointer(skb) - (u8 *)x;
 
-        nlh->nlmsg_len = skb->tail - b;
+        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
         return skb->len;
 
 rtattr_failure:
@@ -767,7 +767,7 @@ static int tca_action_flush(struct rtattr *rta, struct nlmsghdr *n, u32 pid)
                 return -ENOBUFS;
         }
 
-        b = (unsigned char *)skb->tail;
+        b = skb_tail_pointer(skb);
 
         if (rtattr_parse_nested(tb, TCA_ACT_MAX, rta) < 0)
                 goto err_out;
@@ -783,16 +783,16 @@ static int tca_action_flush(struct rtattr *rta, struct nlmsghdr *n, u32 pid)
         t->tca__pad1 = 0;
         t->tca__pad2 = 0;
 
-        x = (struct rtattr *) skb->tail;
+        x = (struct rtattr *)skb_tail_pointer(skb);
         RTA_PUT(skb, TCA_ACT_TAB, 0, NULL);
 
         err = a->ops->walk(skb, &dcb, RTM_DELACTION, a);
         if (err < 0)
                 goto rtattr_failure;
 
-        x->rta_len = skb->tail - (u8 *) x;
+        x->rta_len = skb_tail_pointer(skb) - (u8 *)x;
 
-        nlh->nlmsg_len = skb->tail - b;
+        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
         nlh->nlmsg_flags |= NLM_F_ROOT;
         module_put(a->ops->owner);
         kfree(a);
@@ -884,7 +884,7 @@ static int tcf_add_notify(struct tc_action *a, u32 pid, u32 seq, int event,
         if (!skb)
                 return -ENOBUFS;
 
-        b = (unsigned char *)skb->tail;
+        b = skb_tail_pointer(skb);
 
         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*t), flags);
         t = NLMSG_DATA(nlh);
@@ -892,15 +892,15 @@ static int tcf_add_notify(struct tc_action *a, u32 pid, u32 seq, int event,
         t->tca__pad1 = 0;
         t->tca__pad2 = 0;
 
-        x = (struct rtattr*) skb->tail;
+        x = (struct rtattr *)skb_tail_pointer(skb);
         RTA_PUT(skb, TCA_ACT_TAB, 0, NULL);
 
         if (tcf_action_dump(skb, a, 0, 0) < 0)
                 goto rtattr_failure;
 
-        x->rta_len = skb->tail - (u8*)x;
+        x->rta_len = skb_tail_pointer(skb) - (u8 *)x;
 
-        nlh->nlmsg_len = skb->tail - b;
+        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
         NETLINK_CB(skb).dst_group = RTNLGRP_TC;
 
         err = rtnetlink_send(skb, pid, RTNLGRP_TC, flags&NLM_F_ECHO);
@@ -1015,7 +1015,7 @@ static int
 tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)
 {
         struct nlmsghdr *nlh;
-        unsigned char *b = skb->tail;
+        unsigned char *b = skb_tail_pointer(skb);
         struct rtattr *x;
         struct tc_action_ops *a_o;
         struct tc_action a;
@@ -1048,7 +1048,7 @@ tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)
         t->tca__pad1 = 0;
         t->tca__pad2 = 0;
 
-        x = (struct rtattr *) skb->tail;
+        x = (struct rtattr *)skb_tail_pointer(skb);
         RTA_PUT(skb, TCA_ACT_TAB, 0, NULL);
 
         ret = a_o->walk(skb, cb, RTM_GETACTION, &a);
@@ -1056,12 +1056,12 @@ tc_dump_action(struct sk_buff *skb, struct netlink_callback *cb)
                 goto rtattr_failure;
 
         if (ret > 0) {
-                x->rta_len = skb->tail - (u8 *) x;
+                x->rta_len = skb_tail_pointer(skb) - (u8 *)x;
                 ret = skb->len;
         } else
                 skb_trim(skb, (u8*)x - skb->data);
 
-        nlh->nlmsg_len = skb->tail - b;
+        nlh->nlmsg_len = skb_tail_pointer(skb) - b;
         if (NETLINK_CB(cb->skb).pid && ret)
                 nlh->nlmsg_flags |= NLM_F_MULTI;
         module_put(a_o->owner);