[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/epic100.c b/drivers/net/epic100.c
index 81ebaed..87f5227 100644
--- a/drivers/net/epic100.c
+++ b/drivers/net/epic100.c
@@ -1003,7 +1003,7 @@
skb->dev = dev; /* Mark as being used by this device. */
skb_reserve(skb, 2); /* 16 byte align the IP header. */
ep->rx_ring[i].bufaddr = pci_map_single(ep->pci_dev,
- skb->tail, ep->rx_buf_sz, PCI_DMA_FROMDEVICE);
+ skb->data, ep->rx_buf_sz, PCI_DMA_FROMDEVICE);
ep->rx_ring[i].rxstatus = cpu_to_le32(DescOwn);
}
ep->dirty_rx = (unsigned int)(i - RX_RING_SIZE);
@@ -1274,7 +1274,7 @@
ep->rx_ring[entry].bufaddr,
ep->rx_buf_sz,
PCI_DMA_FROMDEVICE);
- eth_copy_and_sum(skb, ep->rx_skbuff[entry]->tail, pkt_len, 0);
+ eth_copy_and_sum(skb, ep->rx_skbuff[entry]->data, pkt_len, 0);
skb_put(skb, pkt_len);
pci_dma_sync_single_for_device(ep->pci_dev,
ep->rx_ring[entry].bufaddr,
@@ -1308,7 +1308,7 @@
skb->dev = dev; /* Mark as being used by this device. */
skb_reserve(skb, 2); /* Align IP on 16 byte boundaries */
ep->rx_ring[entry].bufaddr = pci_map_single(ep->pci_dev,
- skb->tail, ep->rx_buf_sz, PCI_DMA_FROMDEVICE);
+ skb->data, ep->rx_buf_sz, PCI_DMA_FROMDEVICE);
work_done++;
}
ep->rx_ring[entry].rxstatus = cpu_to_le32(DescOwn);