[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/pcnet32.c b/drivers/net/pcnet32.c
index 3213f3e..113b680 100644
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c
@@ -1602,7 +1602,7 @@
rmb();
if (lp->rx_dma_addr[i] == 0)
- lp->rx_dma_addr[i] = pci_map_single(lp->pci_dev, rx_skbuff->tail,
+ lp->rx_dma_addr[i] = pci_map_single(lp->pci_dev, rx_skbuff->data,
PKT_BUF_SZ-2, PCI_DMA_FROMDEVICE);
lp->rx_ring[i].base = (u32)le32_to_cpu(lp->rx_dma_addr[i]);
lp->rx_ring[i].buf_length = le16_to_cpu(2-PKT_BUF_SZ);
@@ -1983,7 +1983,7 @@
lp->rx_skbuff[entry] = newskb;
newskb->dev = dev;
lp->rx_dma_addr[entry] =
- pci_map_single(lp->pci_dev, newskb->tail,
+ pci_map_single(lp->pci_dev, newskb->data,
PKT_BUF_SZ-2, PCI_DMA_FROMDEVICE);
lp->rx_ring[entry].base = le32_to_cpu(lp->rx_dma_addr[entry]);
rx_in_place = 1;
@@ -2020,7 +2020,7 @@
PKT_BUF_SZ-2,
PCI_DMA_FROMDEVICE);
eth_copy_and_sum(skb,
- (unsigned char *)(lp->rx_skbuff[entry]->tail),
+ (unsigned char *)(lp->rx_skbuff[entry]->data),
pkt_len,0);
pci_dma_sync_single_for_device(lp->pci_dev,
lp->rx_dma_addr[entry],