[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/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 5df71cd..37362cd 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -60,7 +60,7 @@
struct nlmsghdr *nlh;
void *info = NULL;
struct inet_diag_meminfo *minfo = NULL;
- unsigned char *b = skb->tail;
+ unsigned char *b = skb_tail_pointer(skb);
const struct inet_diag_handler *handler;
handler = inet_diag_table[unlh->nlmsg_type];
@@ -147,7 +147,7 @@
icsk->icsk_ca_ops && icsk->icsk_ca_ops->get_info)
icsk->icsk_ca_ops->get_info(sk, ext, skb);
- nlh->nlmsg_len = skb->tail - b;
+ nlh->nlmsg_len = skb_tail_pointer(skb) - b;
return skb->len;
rtattr_failure:
@@ -163,7 +163,7 @@
{
long tmo;
struct inet_diag_msg *r;
- const unsigned char *previous_tail = skb->tail;
+ const unsigned char *previous_tail = skb_tail_pointer(skb);
struct nlmsghdr *nlh = NLMSG_PUT(skb, pid, seq,
unlh->nlmsg_type, sizeof(*r));
@@ -205,7 +205,7 @@
&tw6->tw_v6_daddr);
}
#endif
- nlh->nlmsg_len = skb->tail - previous_tail;
+ nlh->nlmsg_len = skb_tail_pointer(skb) - previous_tail;
return skb->len;
nlmsg_failure:
skb_trim(skb, previous_tail - skb->data);
@@ -535,7 +535,7 @@
{
const struct inet_request_sock *ireq = inet_rsk(req);
struct inet_sock *inet = inet_sk(sk);
- unsigned char *b = skb->tail;
+ unsigned char *b = skb_tail_pointer(skb);
struct inet_diag_msg *r;
struct nlmsghdr *nlh;
long tmo;
@@ -574,7 +574,7 @@
&inet6_rsk(req)->rmt_addr);
}
#endif
- nlh->nlmsg_len = skb->tail - b;
+ nlh->nlmsg_len = skb_tail_pointer(skb) - b;
return skb->len;