Re: [PATCH v3 3/3] powerpc/papr_scm: Force a scm-unbind if initial scm-bind fails

["Oliver O'Halloran" <oohall@gmail.com>]

On Thu, Jun 27, 2019 at 12:58 PM Aneesh Kumar K.V
<aneesh.kumar@linux.ibm.com> wrote:
>
> "Oliver O'Halloran" <oohall@gmail.com> writes:
>
> >> > +             rc = drc_pmem_bind(p);
> >> > +     }
> >> > +
> >> >       if (rc)
> >> >               goto err;
> >> >
> >>
> >> I am also not sure about the module reference count here. Should we
> >> increment the module reference count after a bind so that we can track
> >> failures in ubind and fail the module unload?
> >
> > I don't really get what you're concerned about here. The error
> > handling path calls drc_pmem_unbind() so if there's a bind error we
> > should never leave probe with memory still bound.
> >
>
> In the remove callback, if the ubind fail should we allow the module
> unload?

If the drc_pmem_unbind() in the driver's remove function fails the
driver will still be unbound from the platform device for that DRC.
You can try re-bind the driver to the platform device and it'll hit
the unbind-then-bind again error path this series introduces (which
might also fail), but that's fine. The only reasons I can think of for
drc_pmem_unbind() failing are bugs in the hypervisor or bugs in the
driver. Forcing the module to stay loaded doesn't help either case so
I'm not seeing the benefit.

Oliver