Subject: Re: [PATCHv2 net-next 1/8] skb: report completion status for zero copy skbs

From: "Michael S. Tsirkin" <[email-masked]>
Date: Thu, 1 Nov 2012 18:16:11 +0200

On Thu, Nov 01, 2012 at 11:50:24AM -0400, David Miller wrote:
> From: "Michael S. Tsirkin" <[email-masked]>
> Date: Wed, 31 Oct 2012 12:31:06 +0200
> 
> > -void vhost_zerocopy_callback(struct ubuf_info *ubuf)
> > +void vhost_zerocopy_callback(struct ubuf_info *ubuf, int zerocopy_status)
> 
> If you're only reporting true/false values, even just for now,
> please use 'bool' for this.

In fact next patch reports -ENOMEM when tun hits OOM so callback can
distinguish between copy (>0 value) and error (<0 value)
and reduce zerocopy more aggressively in case of errors.

The *callback* in vhost-net currently handles all non-zero
values identically, but I am not sure it's the optimal behaviour
so I thought it's worth it to give callbacks the info.

Do you think it's over-engineering, or a good idea?

-- 
MST