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Date: Fri, 23 Nov 2012 18:10:07 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 1.3 3/5] qom: make object_delete usable for
 statically-allocated objects
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To: =?ISO-8859-15?Q?Andreas_F=E4rber?= <afaerber@suse.de>
Cc: peter.maydell@linaro.org, aliguori@us.ibm.com, qemu-devel@nongnu.org, Liu Ping Fan <qemulist@gmail.com>

Il 23/11/2012 18:02, Andreas F=E4rber ha scritto:
>> Store in the object the freeing function that will be used at deletion
>> > time.  This makes it possible to use object_delete on statically-all=
ocated
>> > (embedded) objects.  Dually, it makes it possible to use object_unpa=
rent
>> > and object_unref without leaking memory, when the lifetime of object
>> > might extend until after the call to object_delete.
>> >=20
>> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> The code is
>=20
> Reviewed-by: Andreas F=E4rber <afaerber@suse.de>
>=20
> however I do not agree with the goal in the subject. I thought this was
> to match C++ in actually deallocating the memory.

At the "real" end of the series object_delete disappears completely.  I
posted only the initial part because the rest is not appropriate for
1.3, you can see it at https://github.com/bonzini/qemu/commits/qdev-free.

You just have ref/unref to keep an object alive, and unparent to remove i=
t.

qbus_free and qdev_free become simply synonyms for object_unparent.
After the unparent, the refcount is magically zero for the bus/device
and everything below it in the qtree, and they disappear.

Paolo