[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/lasi_82596.c b/drivers/net/lasi_82596.c
index 5e263fc..41bad07 100644
--- a/drivers/net/lasi_82596.c
+++ b/drivers/net/lasi_82596.c
@@ -553,14 +553,14 @@
if (skb == NULL)
panic("%s: alloc_skb() failed", __FILE__);
skb_reserve(skb, 2);
- dma_addr = dma_map_single(lp->dev, skb->tail,PKT_BUF_SZ,
+ dma_addr = dma_map_single(lp->dev, skb->data,PKT_BUF_SZ,
DMA_FROM_DEVICE);
skb->dev = dev;
rbd->v_next = rbd+1;
rbd->b_next = WSWAPrbd(virt_to_dma(lp,rbd+1));
rbd->b_addr = WSWAPrbd(virt_to_dma(lp,rbd));
rbd->skb = skb;
- rbd->v_data = skb->tail;
+ rbd->v_data = skb->data;
rbd->b_data = WSWAPchar(dma_addr);
rbd->size = PKT_BUF_SZ;
}
@@ -783,8 +783,8 @@
rx_in_place = 1;
rbd->skb = newskb;
newskb->dev = dev;
- dma_addr = dma_map_single(lp->dev, newskb->tail, PKT_BUF_SZ, DMA_FROM_DEVICE);
- rbd->v_data = newskb->tail;
+ dma_addr = dma_map_single(lp->dev, newskb->data, PKT_BUF_SZ, DMA_FROM_DEVICE);
+ rbd->v_data = newskb->data;
rbd->b_data = WSWAPchar(dma_addr);
CHECK_WBACK_INV(rbd, sizeof(struct i596_rbd));
}
