[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>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/net/via-rhine.c b/drivers/net/via-rhine.c
index be1c1047b9ba..a56ef0df203a 100644
--- a/drivers/net/via-rhine.c
+++ b/drivers/net/via-rhine.c
@@ -990,7 +990,7 @@ static void alloc_rbufs(struct net_device *dev)
                 skb->dev = dev;                 /* Mark as being used by this device. */
 
                 rp->rx_skbuff_dma[i] =
-                        pci_map_single(rp->pdev, skb->tail, rp->rx_buf_sz,
+                        pci_map_single(rp->pdev, skb->data, rp->rx_buf_sz,
                                        PCI_DMA_FROMDEVICE);
 
                 rp->rx_ring[i].addr = cpu_to_le32(rp->rx_skbuff_dma[i]);
@@ -1518,7 +1518,7 @@ static void rhine_rx(struct net_device *dev)
                                                             PCI_DMA_FROMDEVICE);
 
                                 eth_copy_and_sum(skb,
-                                                 rp->rx_skbuff[entry]->tail,
+                                                 rp->rx_skbuff[entry]->data,
                                                  pkt_len, 0);
                                 skb_put(skb, pkt_len);
                                 pci_dma_sync_single_for_device(rp->pdev,
@@ -1561,7 +1561,7 @@ static void rhine_rx(struct net_device *dev)
                                 break;  /* Better luck next round. */
                         skb->dev = dev; /* Mark as being used by this device. */
                         rp->rx_skbuff_dma[entry] =
-                                pci_map_single(rp->pdev, skb->tail,
+                                pci_map_single(rp->pdev, skb->data,
                                                rp->rx_buf_sz,
                                                PCI_DMA_FROMDEVICE);
                         rp->rx_ring[entry].addr = cpu_to_le32(rp->rx_skbuff_dma[entry]);