Re: find_vqs operation starting at arbitrary index

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Jun 01, 2009 at 02:05:10PM +0530, Amit Shah wrote:
> On (Mon) Jun 01 2009 [11:11:06], Michael S. Tsirkin wrote:
> > On Mon, Jun 01, 2009 at 01:33:48PM +0530, Amit Shah wrote:
> > > Hello,
> > > 
> > > The recent find_vqs operation doesn't allow for a vq to be found at an
> > > arbitrary location; it's meant to be called once at startup to find all
> > > possible queues and never called again.
> > > 
> > > This doesn't work for devices which can have queues hot-plugged at
> > > run-time. This can be made to work by passing the 'start_index' value as
> > > was done earlier for find_vq, but I doubt something like the following
> > > will work. The MSI vectors might need some changing as well.
> > 
> > How, specifically?
> 
> I'm not sure; I was wanting to know if they will.

Yes, probably.

> I suspect this piece
> of code though:
> 
> in vp_find_vqs, just before calling vp_find_vq:
> 
> 	/* How many vectors would we like? */
> 	for (i = 0; i < nvqs; ++i)
> 		if (callbacks[i])
> 			++vectors;
> 
> 	err = vp_request_vectors(vdev, vectors);
> 	if (err)
> 		goto error_request;
> 
> Will any adjusting be needed for the 'vectors' argument (since it's
> considered to be the max value one can specify)?
> 
> 		Amit

Right. And it can only be called once. And something'll have to be done
on cleanup as well.

-- 
MST