[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/atm/he.c b/drivers/atm/he.c
index 8510026..d33aba6 100644
--- a/drivers/atm/he.c
+++ b/drivers/atm/he.c
@@ -1901,13 +1901,13 @@
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;
diff --git a/drivers/atm/idt77252.c b/drivers/atm/idt77252.c
index b4b8014..1e49799 100644
--- a/drivers/atm/idt77252.c
+++ b/drivers/atm/idt77252.c
@@ -1816,7 +1816,8 @@
u32 handle;
u32 addr;
- skb->data = skb->tail = skb->head;
+ skb->data = skb->head;
+ skb_reset_tail_pointer(skb);
skb->len = 0;
skb_reserve(skb, 16);
diff --git a/drivers/atm/nicstar.c b/drivers/atm/nicstar.c
index aab9b37..26f4b70 100644
--- a/drivers/atm/nicstar.c
+++ b/drivers/atm/nicstar.c
@@ -2208,7 +2208,7 @@
if (i == 1 && ns_rsqe_eopdu(rsqe))
*((u32 *) sb->data) |= 0x00000002;
skb_put(sb, NS_AAL0_HEADER);
- memcpy(sb->tail, cell, ATM_CELL_PAYLOAD);
+ memcpy(skb_tail_pointer(sb), cell, ATM_CELL_PAYLOAD);
skb_put(sb, ATM_CELL_PAYLOAD);
ATM_SKB(sb)->vcc = vcc;
__net_timestamp(sb);
@@ -2252,7 +2252,8 @@
vc->rx_iov = iovb;
NS_SKB(iovb)->iovcnt = 0;
iovb->len = 0;
- iovb->tail = iovb->data = iovb->head;
+ iovb->data = iovb->head;
+ skb_reset_tail_pointer(iovb);
NS_SKB(iovb)->vcc = vcc;
/* IMPORTANT: a pointer to the sk_buff containing the small or large
buffer is stored as iovec base, NOT a pointer to the
@@ -2265,7 +2266,8 @@
recycle_iovec_rx_bufs(card, (struct iovec *) iovb->data, NS_MAX_IOVECS);
NS_SKB(iovb)->iovcnt = 0;
iovb->len = 0;
- iovb->tail = iovb->data = iovb->head;
+ iovb->data = iovb->head;
+ skb_reset_tail_pointer(iovb);
NS_SKB(iovb)->vcc = vcc;
}
iov = &((struct iovec *) iovb->data)[NS_SKB(iovb)->iovcnt++];
@@ -2489,7 +2491,7 @@
{
lb = (struct sk_buff *) iov->iov_base;
tocopy = min_t(int, remaining, iov->iov_len);
- memcpy(hb->tail, lb->data, tocopy);
+ memcpy(skb_tail_pointer(hb), lb->data, tocopy);
skb_put(hb, tocopy);
iov++;
remaining -= tocopy;