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Date: Tue, 24 Jul 2018 09:39:16 -0300
From: Eduardo Habkost <ehabkost@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH for-3.1 2/2] acpi: Decouple ACPI hotplug
 callbacks from HotplugHandler
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To: Igor Mammedov <imammedo@redhat.com>
Cc: qemu-devel@nongnu.org, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, Xiao Guangrong <xiaoguangrong.eric@gmail.com>, Ben Warren <ben@skyportsystems.com>, "Michael S. Tsirkin" <mst@redhat.com>

On Tue, Jul 24, 2018 at 02:29:49PM +0200, Igor Mammedov wrote:
> On Mon, 23 Jul 2018 16:31:45 -0300
> Eduardo Habkost <ehabkost@redhat.com> wrote:
> 
> > The ACPI hotplug callbacks get a HotplugHandler object as
> > argument.  This has two problems:
> > 
> > 1) The functions require a TYPE_ACPI_DEVICE_IF object, but the
> >    function prototype doesn't indicate that.  It's possible to
> >    pass an object that would make the function crash.
> > 2) The function does not require the object to implement
> >    TYPE_HOTPLUG_HANDLER at all, but the function prototype
> >    imposes that for no reason.
> > 
> > Change the argument type to AcpiDeviceIf instead of
> > HotplugHandler.
> What is the motivation for this patch,
> do you actually get crashes?

I didn't get crashes, but the idea for the change came when
Michael asked me how to get the HotplugHandler object.  I was
going to suggest current_machine (which is also a hotplug
handler), when I noticed he actually needed an AcpiDeviceIf
object.

The main motivation, however, is to simply make the function
prototypes make sense.  Is there a single reason to make the ACPI
functions get a HotplugHandler argument instead of AcpiDeviceIf?

-- 
Eduardo