Re: [Qemu-ppc] [Qemu-devel] [for-2.10 PATCH] spapr_drc: fix realize and unrealize

[David Gibson]

On Thu, Jul 27, 2017 at 03:50:37PM -0500, Michael Roth wrote:
> Quoting Greg Kurz (2017-07-27 08:45:47)
> > If object_property_add_alias() returns an error in realize(), we should
> > propagate it to the caller and certainly not unref the DRC.
> 
> Indeed. I think that was the result of this part of the code
> originally living in spapr_dr_connector_new() during development,
> where it had previously made sense to free the object if there was a
> failure and then return NULL. We definitely shouldn't be during it
> now...

Yes, I think that's right.

I've applied this fix to ppc-for-2.10.

> 
> > 
> > Same thing goes for unrealize(). Since object_property_del() is the last
> > call, we can even get rid of the intermediate Error *.
> > 
> > And finally, unrealize() should undo all registrations performed by
> > realize().
> > 
> > Signed-off-by: Greg Kurz <address@hidden>
> > ---
> > 
> > David,
> > 
> > As agreed on the list, here's the version of the fix for 2.10. I'll respin
> > my PHB hotplug series on top of it.
> > 
> 
> 
> Since spapr_dr_connector_new() calls realize() with errp = NULL, we
> basically lose the error now. I think maybe we should at least report it
> still, but even better would be to have _new() call object_property_* with
> error_abort, since callers of spapr_dr_connector_new() don't all check
> for the return value and even if they did the appropriate action would
> always be to report+abort() anyway.

I agree.  Well, except I think it should be &error_fatal, not
&error_abort.  But that can be a follow up patch.

> 
> Looks good otherwise.
> 
> >      }
> > -    g_free(child_name);
> >      vmstate_register(DEVICE(drc), spapr_drc_index(drc), &vmstate_spapr_drc,
> >                       drc);
> >      qemu_register_reset(drc_reset, drc);
> > @@ -522,16 +522,13 @@ static void unrealize(DeviceState *d, Error **errp)
> >      sPAPRDRConnector *drc = SPAPR_DR_CONNECTOR(d);
> >      Object *root_container;
> >      char name[256];
> > -    Error *err = NULL;
> > 
> >      trace_spapr_drc_unrealize(spapr_drc_index(drc));
> > +    qemu_unregister_reset(drc_reset, drc);
> > +    vmstate_unregister(DEVICE(drc), &vmstate_spapr_drc, drc);
> >      root_container = container_get(object_get_root(), DRC_CONTAINER_PATH);
> >      snprintf(name, sizeof(name), "%x", spapr_drc_index(drc));
> > -    object_property_del(root_container, name, &err);
> > -    if (err) {
> > -        error_report_err(err);
> > -        object_unref(OBJECT(drc));
> > -    }
> > +    object_property_del(root_container, name, errp);
> >  }
> > 
> >  sPAPRDRConnector *spapr_dr_connector_new(Object *owner, const char *type,
> > 
> > 
> 

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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