[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/decnet/dn_table.c b/net/decnet/dn_table.c
index 780a141..544c455 100644
--- a/net/decnet/dn_table.c
+++ b/net/decnet/dn_table.c
@@ -295,7 +295,7 @@
{
struct rtmsg *rtm;
struct nlmsghdr *nlh;
- unsigned char *b = skb->tail;
+ unsigned char *b = skb_tail_pointer(skb);
nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*rtm), flags);
rtm = NLMSG_DATA(nlh);
@@ -337,13 +337,13 @@
nhp->rtnh_ifindex = nh->nh_oif;
if (nh->nh_gw)
RTA_PUT(skb, RTA_GATEWAY, 2, &nh->nh_gw);
- nhp->rtnh_len = skb->tail - (unsigned char *)nhp;
+ nhp->rtnh_len = skb_tail_pointer(skb) - (unsigned char *)nhp;
} endfor_nexthops(fi);
mp_head->rta_type = RTA_MULTIPATH;
- mp_head->rta_len = skb->tail - (u8*)mp_head;
+ mp_head->rta_len = skb_tail_pointer(skb) - (u8 *)mp_head;
}
- nlh->nlmsg_len = skb->tail - b;
+ nlh->nlmsg_len = skb_tail_pointer(skb) - b;
return skb->len;