Re: [PATCH net] virtio-net: reject small vring sizes

[Alvaro Karsz]

> > I see your point.
> > Regardless, we'll need to fail probe in some cases.
> > ring size of 1 for example (if I'm not mistaken)
> 
> Hmm. We can make it work if we increase hard header size, then
> there will always be room for vnet header.
> 
> > control vq even needs a bigger ring.
> 
> Why does it?

At the moment, most of the commands chain 3 descriptors:
1 - class + command
2 - command specific
3 - ack

We could merge 1 and 2 into a single one, both are read only for the device, so I take it back, it won't need a bigger ring.
But it will need 2 descriptors at least(1 read only for the device and 1 write only for the device), so we still need to fail probe sometimes.