[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/asix.c b/drivers/usb/net/asix.c
index 5808ea0..f56e2da 100644
--- a/drivers/usb/net/asix.c
+++ b/drivers/usb/net/asix.c
@@ -298,7 +298,7 @@
if (ax_skb) {
ax_skb->len = size;
ax_skb->data = packet;
- ax_skb->tail = packet + size;
+ skb_set_tail_pointer(ax_skb, size);
usbnet_skb_return(dev, ax_skb);
} else {
return 0;
@@ -338,7 +338,7 @@
&& ((headroom + tailroom) >= (4 + padlen))) {
if ((headroom < 4) || (tailroom < padlen)) {
skb->data = memmove(skb->head + 4, skb->data, skb->len);
- skb->tail = skb->data + skb->len;
+ skb_set_tail_pointer(skb, skb->len);
}
} else {
struct sk_buff *skb2;
@@ -356,7 +356,7 @@
if ((skb->len % 512) == 0) {
cpu_to_le32s(&padbytes);
- memcpy( skb->tail, &padbytes, sizeof(padbytes));
+ memcpy(skb_tail_pointer(skb), &padbytes, sizeof(padbytes));
skb_put(skb, sizeof(padbytes));
}
return skb;
