[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/ipmr.c b/net/ipv4/ipmr.c
index 50d0b301..ea0a491 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -513,7 +513,8 @@
struct nlmsghdr *nlh = (struct nlmsghdr *)skb_pull(skb, sizeof(struct iphdr));
if (ipmr_fill_mroute(skb, c, NLMSG_DATA(nlh)) > 0) {
- nlh->nlmsg_len = skb->tail - (u8*)nlh;
+ nlh->nlmsg_len = (skb_tail_pointer(skb) -
+ (u8 *)nlh);
} else {
nlh->nlmsg_type = NLMSG_ERROR;
nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct nlmsgerr));
@@ -580,7 +581,7 @@
* Copy the IP header
*/
- skb_set_network_header(skb, skb->tail - skb->data);
+ skb->network_header = skb->tail;
skb_put(skb, ihl);
memcpy(skb->data,pkt->data,ihl);
ip_hdr(skb)->protocol = 0; /* Flag to the kernel this is a route add */
@@ -1544,7 +1545,7 @@
int ct;
struct rtnexthop *nhp;
struct net_device *dev = vif_table[c->mfc_parent].dev;
- u8 *b = skb->tail;
+ u8 *b = skb_tail_pointer(skb);
struct rtattr *mp_head;
if (dev)
@@ -1564,7 +1565,7 @@
}
}
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;
rtm->rtm_type = RTN_MULTICAST;
return 1;