[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/sb1250-mac.c b/drivers/net/sb1250-mac.c
index fd2e7c3..7abd55a 100644
--- a/drivers/net/sb1250-mac.c
+++ b/drivers/net/sb1250-mac.c
@@ -963,11 +963,11 @@
/*
* Do not interrupt per DMA transfer.
*/
- dsc->dscr_a = virt_to_phys(sb_new->tail) |
+ dsc->dscr_a = virt_to_phys(sb_new->data) |
V_DMA_DSCRA_A_SIZE(NUMCACHEBLKS(pktsize+ETHER_ALIGN)) |
0;
#else
- dsc->dscr_a = virt_to_phys(sb_new->tail) |
+ dsc->dscr_a = virt_to_phys(sb_new->data) |
V_DMA_DSCRA_A_SIZE(NUMCACHEBLKS(pktsize+ETHER_ALIGN)) |
M_DMA_DSCRA_INTERRUPT;
#endif