Re: [PATCH] virtio-blk: Fix kconfig option

From: Michael S. Tsirkin
Date: Thu Sep 06 2012 - 05:48:30 EST


On Thu, Sep 06, 2012 at 02:25:12AM -0700, Kent Overstreet wrote:
> On Thu, Sep 06, 2012 at 11:44:03AM +0300, Michael S. Tsirkin wrote:
> > On Thu, Sep 06, 2012 at 12:41:13AM -0700, Kent Overstreet wrote:
> > > On Tue, Sep 04, 2012 at 03:53:53PM +0930, Rusty Russell wrote:
> > > > Kent Overstreet <koverstreet@xxxxxxxxxx> writes:
> > > >
> > > > > CONFIG_VIRTIO isn't exposed, everything else is supposed to select it
> > > > > instead.
> > > >
> > > > This is a slight mis-understanding. It's supposed to be selected by
> > > > the particular driver, probably virtio_pci in your case.
> > >
> > > So are you saying virtio-blk depends on virtio-pci? If so, the kconfig
> > > should have that.
> > >
> > > As is, VIRTIO_BLK just has:
> > > depends on EXPERIMENTAL && VIRTIO
> > >
> > > which is flat out broken.
> >
> > I don't think anything is broken.
> > Can you show an example of a broken configuration?
>
> Do you not understand the difference between depends an selects?
> Or did you not read my original mail?
> Flip off everything in drivers -> virtio
>
> Now go to drivers -> block and try to turn on virtio-blk.
>
> It's not listed!

Yes. Because you disabled all virtio backends.
It does not make sense to have any frontends.

> Now go back to drivers -> virtio and turn on (randomly) balloon.
>
> Go back to drivers -> block, and now you can turn on virtio-blk!
>
> Do you see what's wrong with this picture?

Yes. You got unlucky with your random guess.
It's a bug in balloon kconfig: it should not
select virtio.
I sent a patch to fix that yesterday.

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