Subject: Re: [PATCH] net: tun: convert to hw_features

From: Rusty Russell <[email-masked]>
Date: Wed, 27 Apr 2011 14:29:31 +0930

On Wed, 20 Apr 2011 01:32:16 -0700 (PDT), David Miller <[email-masked]> wrote:
> From: Michał Mirosław <[email-masked]>
> Date: Tue, 19 Apr 2011 18:13:10 +0200 (CEST)
> 
> > This changes offload setting behaviour to what I think is correct:
> >  - offloads set via ethtool mean what admin wants to use (by default
> >    he wants 'em all)
> >  - offloads set via ioctl() mean what userspace is expecting to get
> >    (this limits which admin wishes are granted)
> >  - TUN_NOCHECKSUM is ignored, as it might cause broken packets when
> >    forwarded (ip_summed == CHECKSUM_UNNECESSARY means that checksum
> >    was verified, not that it can be ignored)
> > 
> > If TUN_NOCHECKSUM is implemented, it should set skb->csum_* and
> > skb->ip_summed (= CHECKSUM_PARTIAL) for known protocols and let others
> > be verified by kernel when necessary.
> > 
> > TUN_NOCHECKSUM handling was introduced by commit
> > f43798c27684ab925adde7d8acc34c78c6e50df8:
> > 
> >     tun: Allow GSO using virtio_net_hdr
> >     
> > Signed-off-by: Michał Mirosław <[email-masked]>
> 
> Applied.

Dave, you just removed a feature that has been in Linux since before
git.  It *probably* just means we go slower in cases we don't really
care about.  But does removing it break qemu?  Has anyone tested?

Thanks,
Rusty.