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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/3c515.c
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@@ -822,7 +822,7 @@ static int corkscrew_open(struct net_device *dev)
break; /* Bad news! */
skb->dev = dev; /* Mark as being used by this device. */
skb_reserve(skb, 2); /* Align IP on 16 byte boundaries */
vp->rx_ring[i].addr = isa_virt_to_bus(skb->tail);
vp->rx_ring[i].addr = isa_virt_to_bus(skb->data);
}
vp->rx_ring[i - 1].next = isa_virt_to_bus(&vp->rx_ring[0]); /* Wrap the ring. */
outl(isa_virt_to_bus(&vp->rx_ring[0]), ioaddr + UpListPtr);
@@ -1406,7 +1406,7 @@ static int boomerang_rx(struct net_device *dev)
break; /* Bad news! */
skb->dev = dev; /* Mark as being used by this device. */
skb_reserve(skb, 2); /* Align IP on 16 byte boundaries */
vp->rx_ring[entry].addr = isa_virt_to_bus(skb->tail);
vp->rx_ring[entry].addr = isa_virt_to_bus(skb->data);
vp->rx_skbuff[entry] = skb;
}
vp->rx_ring[entry].status = 0; /* Clear complete bit. */