Re: [PATCH v4 2/5] xen/pciback: Don't deadlock when unbinding.

[Konrad Rzeszutek Wilk]

On Fri, Jul 11, 2014 at 05:02:01PM -0400, Konrad Rzeszutek Wilk wrote:
> > >--- a/drivers/xen/xen-pciback/pci_stub.c
> > >+++ b/drivers/xen/xen-pciback/pci_stub.c
> > >@@ -250,6 +250,8 @@ struct pci_dev *pcistub_get_pci_dev(struct xen_pcibk_device *pdev,
> > >   *  - 'echo BDF > unbind' with a guest still using it. See pcistub_remove
> > >   *
> > >   *  As such we have to be careful.
> > >+ *
> > >+ *  To make this easier, the caller has to hold the device lock.
> > 
> > Should we assert that the lock is being held?
> 
> Yes of course we should. Thank you!

How about this: