Messages in this thread Patch in this message | | | Subject | Re: skb_padto and small fragmented transmits | From | Chris Leech <> | Date | 06 Feb 2003 11:22:51 -0800 |
| |
On Thu, 2003-02-06 at 03:58, David S. Miller wrote:
> skb_padto() only works on linear skb.
The result is always a linear skb. Given that skb_padto() takes into account data_len (incorrectly, but still) and skb_pad() contains a comment about non-linear skb always having zero tailroom, it certainly looks like these were written with the attempt to work for non-linear buffers.
I fail to see how the statement "skb->len + skb->data_len" has any usable meaning, or how it can be anything other than a bug.
The checksum issue I mentioned is not as clear. I haven't looked at all the callers of skb_copy_expand() and copy_skb_header() to see what effect copying ip_summed in one of those calls might have elsewhere.
> And if you look at all the drivers where it is used, they > do not enable things like scatter-gather.
So because the problem is not currently exposed, it's acceptable for the code to be incorrect?
-- Chris
diff -aur a/include/linux/skbuff.h b/include/linux/skbuff.h --- a/include/linux/skbuff.h 2003-01-13 12:45:20.000000000 -0800 +++ b/include/linux/skbuff.h 2003-02-05 12:25:38.000000000 -0800 @@ -1102,7 +1102,7 @@ static inline struct sk_buff *skb_padto(struct sk_buff *skb, unsigned int len) { - unsigned int size = skb->len + skb->data_len; + unsigned int size = skb->len; if (likely(size >= len)) return skb; return skb_pad(skb, len-size);
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |