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[NET]: Remove gratuitous use of skb->tail in network drivers.

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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>
This commit is contained in:
David S. Miller
2005-06-28 15:25:31 -07:00
parent f835e471b5
commit 689be43945
31 changed files with 95 additions and 97 deletions
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4
drivers/net/typhoon.c
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@@ -1661,7 +1661,7 @@ typhoon_alloc_rx_skb(struct typhoon *tp, u32 idx)
#endif
skb->dev = tp->dev;
dma_addr = pci_map_single(tp->pdev, skb->tail,
dma_addr = pci_map_single(tp->pdev, skb->data,
PKT_BUF_SZ, PCI_DMA_FROMDEVICE);
/* Since no card does 64 bit DAC, the high bits will never
@@ -1721,7 +1721,7 @@ typhoon_rx(struct typhoon *tp, struct basic_ring *rxRing, volatile u32 * ready,
pci_dma_sync_single_for_cpu(tp->pdev, dma_addr,
PKT_BUF_SZ,
PCI_DMA_FROMDEVICE);
eth_copy_and_sum(new_skb, skb->tail, pkt_len, 0);
eth_copy_and_sum(new_skb, skb->data, pkt_len, 0);
pci_dma_sync_single_for_device(tp->pdev, dma_addr,
PKT_BUF_SZ,
PCI_DMA_FROMDEVICE);