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[NET]: Remove gratuitous use of skb->tail in network drivers.

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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>
This commit is contained in:
David S. Miller
2005-06-28 15:25:31 -07:00
parent f835e471b5
commit 689be43945
31 changed files with 95 additions and 97 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/net/lasi_82596.c
+4 -4
View File
@@ -553,14 +553,14 @@ static inline void init_rx_bufs(struct net_device *dev)
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 @@ static inline int i596_rx(struct net_device *dev)
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));
}