Re: [Qemu-devel] [PATCH 1/4] Introduce a new hotplug state: Force eject.

[Anthony Liguori <anthony@codemonkey.ws>]

On 05/16/2012 06:23 AM, Paolo Bonzini wrote:
> Il 16/05/2012 13:15, Anthony PERARD ha scritto:
>>>>          qdev_unplug(&(d->qdev), NULL);
>>>> +        qdev_free(&(d->qdev));
>>>>      }
>>>>   }
>>>>
>>>>
>>>> Anthony, can you confirm that this solves the problem for you?
>> This work until I try to hotplug a new device to the guest at wish
>> point I have this:
>> ERROR:/local/home/anthony/work/qemu/qom/object.c:389:object_delete:
>> assertion failed: (obj->ref == 0)
>>
>> This is because there is still a pending request of the hotunplug in
>> the acpi piix4.
>> If I call qdev_free without qdev_unplug, I hit the same assert, but
>> rigth away. This is way something new.
>
> Because it's missing the object_unparent done by qdev_unplug.  Does
> object_unparent+qdev_free work?  (I believe object_unparent should be
> done by qdev_free rather than qdev_unplug, but that's something for 1.2).

qdev_free() is trivially object_delete today.

What we should do is make an object_destroy() which emits a destroy event and 
then decrements the reference count.  When ref == 0, we should emit a delete event.

We could then register a slot to object_unparent in the destroy event handler, 
and then object_new() could register a free handler in the delete event.

Then object_delete()/qdev_free() just become trivial invocations of object_unref().

But for 1.1, we definitely should just do an explicit object_unparent().

Regards,

Anthony Liguori

>
> Paolo