[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, 1 insertions, 1 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index a6a275db88c..275d2e812a4 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -51,7 +51,7 @@
 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
 {
         const unsigned char *nh = skb_network_header(skb);
-        int packet_len = skb->tail - nh;
+        int packet_len = skb->tail - skb->network_header;
         struct ipv6_opt_hdr *hdr;
         int len;