[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, 2 insertions, 2 deletions

diff --git a/drivers/atm/he.c b/drivers/atm/he.c
index 8510026b690a..d33aba6864c2 100644
--- a/drivers/atm/he.c
+++ b/drivers/atm/he.c
@@ -1901,13 +1901,13 @@ he_service_rbrq(struct he_dev *he_dev, int group)
                         case ATM_AAL0:
                                 /* 2.10.1.5 raw cell receive */
                                 skb->len = ATM_AAL0_SDU;
-                                skb->tail = skb->data + skb->len;
+                                skb_set_tail_pointer(skb, skb->len);
                                 break;
                         case ATM_AAL5:
                                 /* 2.10.1.2 aal5 receive */
 
                                 skb->len = AAL5_LEN(skb->data, he_vcc->pdu_len);
-                                skb->tail = skb->data + skb->len;
+                                skb_set_tail_pointer(skb, skb->len);
 #ifdef USE_CHECKSUM_HW
                                 if (vcc->vpi == 0 && vcc->vci >= ATM_NOT_RSV_VCI) {
                                         skb->ip_summed = CHECKSUM_COMPLETE;