[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/drivers/usb/net/gl620a.c b/drivers/usb/net/gl620a.c
index d257a8e..031cf5c 100644
--- a/drivers/usb/net/gl620a.c
+++ b/drivers/usb/net/gl620a.c
@@ -157,7 +157,7 @@
if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
skb->data = memmove(skb->head + (4 + 4*1),
skb->data, skb->len);
- skb->tail = skb->data + skb->len;
+ skb_set_tail_pointer(skb, skb->len);
}
} else {
struct sk_buff *skb2;