[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/net/tulip/uli526x.c b/drivers/net/tulip/uli526x.c
index 9a5850f..e46f4cb 100644
--- a/drivers/net/tulip/uli526x.c
+++ b/drivers/net/tulip/uli526x.c
@@ -829,7 +829,9 @@
!= NULL) ) {
/* size less than COPY_SIZE, allocate a rxlen SKB */
skb_reserve(skb, 2); /* 16byte align */
- memcpy(skb_put(skb, rxlen), rxptr->rx_skb_ptr->tail, rxlen);
+ memcpy(skb_put(skb, rxlen),
+ skb_tail_pointer(rxptr->rx_skb_ptr),
+ rxlen);
uli526x_reuse_skb(db, rxptr->rx_skb_ptr);
} else
skb_put(skb, rxlen);
@@ -1175,7 +1177,10 @@
if (!(rxptr->rdes0 & cpu_to_le32(0x80000000))) {
rxptr->rx_skb_ptr = skb;
- rxptr->rdes2 = cpu_to_le32( pci_map_single(db->pdev, skb->tail, RX_ALLOC_SIZE, PCI_DMA_FROMDEVICE) );
+ rxptr->rdes2 = cpu_to_le32(pci_map_single(db->pdev,
+ skb_tail_pointer(skb),
+ RX_ALLOC_SIZE,
+ PCI_DMA_FROMDEVICE));
wmb();
rxptr->rdes0 = cpu_to_le32(0x80000000);
db->rx_avail_cnt++;
@@ -1339,7 +1344,10 @@
if ( ( skb = dev_alloc_skb(RX_ALLOC_SIZE) ) == NULL )
break;
rxptr->rx_skb_ptr = skb; /* FIXME (?) */
- rxptr->rdes2 = cpu_to_le32( pci_map_single(db->pdev, skb->tail, RX_ALLOC_SIZE, PCI_DMA_FROMDEVICE) );
+ rxptr->rdes2 = cpu_to_le32(pci_map_single(db->pdev,
+ skb_tail_pointer(skb),
+ RX_ALLOC_SIZE,
+ PCI_DMA_FROMDEVICE));
wmb();
rxptr->rdes0 = cpu_to_le32(0x80000000);
rxptr = rxptr->next_rx_desc;