[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, 7 insertions, 7 deletions

diff --git a/net/irda/qos.c b/net/irda/qos.c
index 349012c926b7..aeb18cf1dcae 100644
--- a/net/irda/qos.c
+++ b/net/irda/qos.c
@@ -469,49 +469,49 @@ int irlap_insert_qos_negotiation_params(struct irlap_cb *self,
         int ret;
 
         /* Insert data rate */
-        ret = irda_param_insert(self, PI_BAUD_RATE, skb->tail,
+        ret = irda_param_insert(self, PI_BAUD_RATE, skb_tail_pointer(skb),
                                 skb_tailroom(skb), &irlap_param_info);
         if (ret < 0)
                 return ret;
         skb_put(skb, ret);
 
         /* Insert max turnaround time */
-        ret = irda_param_insert(self, PI_MAX_TURN_TIME, skb->tail,
+        ret = irda_param_insert(self, PI_MAX_TURN_TIME, skb_tail_pointer(skb),
                                 skb_tailroom(skb), &irlap_param_info);
         if (ret < 0)
                 return ret;
         skb_put(skb, ret);
 
         /* Insert data size */
-        ret = irda_param_insert(self, PI_DATA_SIZE, skb->tail,
+        ret = irda_param_insert(self, PI_DATA_SIZE, skb_tail_pointer(skb),
                                 skb_tailroom(skb), &irlap_param_info);
         if (ret < 0)
                 return ret;
         skb_put(skb, ret);
 
         /* Insert window size */
-        ret = irda_param_insert(self, PI_WINDOW_SIZE, skb->tail,
+        ret = irda_param_insert(self, PI_WINDOW_SIZE, skb_tail_pointer(skb),
                                 skb_tailroom(skb), &irlap_param_info);
         if (ret < 0)
                 return ret;
         skb_put(skb, ret);
 
         /* Insert additional BOFs */
-        ret = irda_param_insert(self, PI_ADD_BOFS, skb->tail,
+        ret = irda_param_insert(self, PI_ADD_BOFS, skb_tail_pointer(skb),
                                 skb_tailroom(skb), &irlap_param_info);
         if (ret < 0)
                 return ret;
         skb_put(skb, ret);
 
         /* Insert minimum turnaround time */
-        ret = irda_param_insert(self, PI_MIN_TURN_TIME, skb->tail,
+        ret = irda_param_insert(self, PI_MIN_TURN_TIME, skb_tail_pointer(skb),
                                 skb_tailroom(skb), &irlap_param_info);
         if (ret < 0)
                 return ret;
         skb_put(skb, ret);
 
         /* Insert link disconnect/threshold time */
-        ret = irda_param_insert(self, PI_LINK_DISC, skb->tail,
+        ret = irda_param_insert(self, PI_LINK_DISC, skb_tail_pointer(skb),
                                 skb_tailroom(skb), &irlap_param_info);
         if (ret < 0)
                 return ret;