Re: [PATCH 22/25] xen: xen-netfront: use skb.cb for storing private data

[Jeremy Fitzhardinge <jeremy@goop.org>]

Herbert Xu wrote:
> Sure thing.  I'll look over it soon.
>
> Actually there is one thing I'd like to see changed first up: I noticed
> that you've stripped out the checksum hack which is in the main Xen tree.
> We actually have the code in net-2.6.22 (which is also in mm) that lets
> you use CHECKSUM_PARTIAL on received packets without having to do that
> hack.
>
> Here's the patch that I've been testing so far.  It's against the Xen
> source, but should be easy to adapt to your version as well.
>
> I just thought about this again, and in fact we need this change for
> correctness as well as performance.  Because not setting ip_summed
> to CHECKSUM_PARTIAL in netfront is not going to stop netback from
> sending CHECKSUM_PARTIAL packets to us.  If these packets are then
> routed/bridged back to netback, they'll have the wrong checksum.
>   

OK, I've been sitting on this in the hope that I'll suddenly see the
light and work out what you're talking about - but apparently that's not
going to happen.  So, some questions:

   1. Does this patch change the dom0 <-> domU interface?  or does it
      fix something that's currently broken?
   2. Can just apply the netfront part to the pv_ops kernel, or does it
      require the corresponding dom0 patch to be applied as well?

Thanks,
    J