[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/via-velocity.c b/drivers/net/via-velocity.c
index 15e7102..abc5cee 100644
--- a/drivers/net/via-velocity.c
+++ b/drivers/net/via-velocity.c
@@ -1335,7 +1335,7 @@
if (vptr->flags & VELOCITY_FLAGS_IP_ALIGN)
skb_reserve(new_skb, 2);
- memcpy(new_skb->data, rx_skb[0]->tail, pkt_size);
+ memcpy(new_skb->data, rx_skb[0]->data, pkt_size);
*rx_skb = new_skb;
ret = 0;
}
@@ -1456,9 +1456,9 @@
* Do the gymnastics to get the buffer head for data at
* 64byte alignment.
*/
- skb_reserve(rd_info->skb, (unsigned long) rd_info->skb->tail & 63);
+ skb_reserve(rd_info->skb, (unsigned long) rd_info->skb->data & 63);
rd_info->skb->dev = vptr->dev;
- rd_info->skb_dma = pci_map_single(vptr->pdev, rd_info->skb->tail, vptr->rx_buf_sz, PCI_DMA_FROMDEVICE);
+ rd_info->skb_dma = pci_map_single(vptr->pdev, rd_info->skb->data, vptr->rx_buf_sz, PCI_DMA_FROMDEVICE);
/*
* Fill in the descriptor to match