[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/3c515.c b/drivers/net/3c515.c
index d272ea3..91d1c4c 100644
--- a/drivers/net/3c515.c
+++ b/drivers/net/3c515.c
@@ -822,7 +822,7 @@
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 @@
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. */
