[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/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
index 94f45736056..10cc13cfae6 100644
--- a/net/bluetooth/rfcomm/core.c
+++ b/net/bluetooth/rfcomm/core.c
@@ -1567,7 +1567,7 @@ static int rfcomm_recv_frame(struct rfcomm_session *s, struct sk_buff *skb)
 
         /* Trim FCS */
         skb->len--; skb->tail--;
-        fcs = *(u8 *) skb->tail;
+        fcs = *(u8 *)skb_tail_pointer(skb);
 
         if (__check_fcs(skb->data, type, fcs)) {
                 BT_ERR("bad checksum in packet");