[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/via-rhine.c b/drivers/net/via-rhine.c
index be1c104..a56ef0d 100644
--- a/drivers/net/via-rhine.c
+++ b/drivers/net/via-rhine.c
@@ -990,7 +990,7 @@
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 @@
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 @@
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]);