[NET]: Remove gratuitous use of skb->tail in network drivers.
Many drivers use skb->tail unnecessarily.
In these situations, the code roughly looks like:
dev = dev_alloc_skb(...);
[optional] skb_reserve(skb, ...);
... skb->tail ...
But even if the skb_reserve() happens, skb->data equals
skb->tail. So it doesn't make any sense to use anything
other than skb->data in these cases.
Another case was the s2io.c driver directly mucking with
the skb->data and skb->tail pointers. It really just wanted
to do an skb_reserve(), so that's what the code was changed
to do instead.
Another reason I'm making this change as it allows some SKB
cleanups I have planned simpler to merge. In those cleanups,
skb->head, skb->tail, and skb->end pointers are removed, and
replaced with skb->head_room and skb->tail_room integers.
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index ce449fe..d5afe05 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -1876,7 +1876,7 @@
skb_reserve(skb, NET_IP_ALIGN);
*sk_buff = skb;
- mapping = pci_map_single(pdev, skb->tail, rx_buf_sz,
+ mapping = pci_map_single(pdev, skb->data, rx_buf_sz,
PCI_DMA_FROMDEVICE);
rtl8169_map_to_asic(desc, mapping, rx_buf_sz);
@@ -2336,7 +2336,7 @@
skb = dev_alloc_skb(pkt_size + NET_IP_ALIGN);
if (skb) {
skb_reserve(skb, NET_IP_ALIGN);
- eth_copy_and_sum(skb, sk_buff[0]->tail, pkt_size, 0);
+ eth_copy_and_sum(skb, sk_buff[0]->data, pkt_size, 0);
*sk_buff = skb;
rtl8169_mark_to_asic(desc, rx_buf_sz);
ret = 0;