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

From: Jeremy Fitzhardinge
Date: Fri Apr 27 2007 - 18:21:08 EST

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?

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at