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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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8
drivers/net/dl2k.c
View File

@@ -547,7 +547,7 @@ rio_timer (unsigned long data)
skb_reserve (skb, 2);
np->rx_ring[entry].fraginfo =
cpu_to_le64 (pci_map_single
(np->pdev, skb->tail, np->rx_buf_sz,
(np->pdev, skb->data, np->rx_buf_sz,
PCI_DMA_FROMDEVICE));
}
np->rx_ring[entry].fraginfo |=
@@ -618,7 +618,7 @@ alloc_list (struct net_device *dev)
/* Rubicon now supports 40 bits of addressing space. */
np->rx_ring[i].fraginfo =
cpu_to_le64 ( pci_map_single (
np->pdev, skb->tail, np->rx_buf_sz,
np->pdev, skb->data, np->rx_buf_sz,
PCI_DMA_FROMDEVICE));
np->rx_ring[i].fraginfo |= cpu_to_le64 (np->rx_buf_sz) << 48;
}
@@ -906,7 +906,7 @@ receive_packet (struct net_device *dev)
/* 16 byte align the IP header */
skb_reserve (skb, 2);
eth_copy_and_sum (skb,
np->rx_skbuff[entry]->tail,
np->rx_skbuff[entry]->data,
pkt_len, 0);
skb_put (skb, pkt_len);
pci_dma_sync_single_for_device(np->pdev,
@@ -950,7 +950,7 @@ receive_packet (struct net_device *dev)
skb_reserve (skb, 2);
np->rx_ring[entry].fraginfo =
cpu_to_le64 (pci_map_single
(np->pdev, skb->tail, np->rx_buf_sz,
(np->pdev, skb->data, np->rx_buf_sz,
PCI_DMA_FROMDEVICE));
}
np->rx_ring[entry].fraginfo |=