[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/eepro100.c b/drivers/net/eepro100.c
index 98b3a2f..1795425 100644
--- a/drivers/net/eepro100.c
+++ b/drivers/net/eepro100.c
@@ -1269,7 +1269,7 @@
if (skb == NULL)
break; /* OK. Just initially short of Rx bufs. */
skb->dev = dev; /* Mark as being used by this device. */
- rxf = (struct RxFD *)skb->tail;
+ rxf = (struct RxFD *)skb->data;
sp->rx_ringp[i] = rxf;
sp->rx_ring_dma[i] =
pci_map_single(sp->pdev, rxf,
@@ -1661,7 +1661,7 @@
sp->rx_ringp[entry] = NULL;
return NULL;
}
- rxf = sp->rx_ringp[entry] = (struct RxFD *)skb->tail;
+ rxf = sp->rx_ringp[entry] = (struct RxFD *)skb->data;
sp->rx_ring_dma[entry] =
pci_map_single(sp->pdev, rxf,
PKT_BUF_SZ + sizeof(struct RxFD), PCI_DMA_FROMDEVICE);
@@ -1808,10 +1808,10 @@
#if 1 || USE_IP_CSUM
/* Packet is in one chunk -- we can copy + cksum. */
- eth_copy_and_sum(skb, sp->rx_skbuff[entry]->tail, pkt_len, 0);
+ eth_copy_and_sum(skb, sp->rx_skbuff[entry]->data, pkt_len, 0);
skb_put(skb, pkt_len);
#else
- memcpy(skb_put(skb, pkt_len), sp->rx_skbuff[entry]->tail,
+ memcpy(skb_put(skb, pkt_len), sp->rx_skbuff[entry]->data,
pkt_len);
#endif
pci_dma_sync_single_for_device(sp->pdev, sp->rx_ring_dma[entry],
