[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/tipc/socket.c b/net/tipc/socket.c
index b71739f..45832fb 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1020,7 +1020,7 @@
if (!err) {
buf_crs = (unsigned char *)(TIPC_SKB_CB(buf)->handle);
- sz = buf->tail - buf_crs;
+ sz = skb_tail_pointer(buf) - buf_crs;
needed = (buf_len - sz_copied);
sz_to_copy = (sz <= needed) ? sz : needed;
