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Date: Thu, 11 Mar 2010 15:42:03 +0200
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] Re: [PATCH 1/7] Add support for generic notifier
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References: <1268239869-16058-1-git-send-email-aliguori@us.ibm.com>	<201003111257.59828.paul@codesourcery.com>
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, Anthony Liguori <aliguori@us.ibm.com>, Gerd Hoffman <kraxel@redhat.com>, Paul Brook <paul@codesourcery.com>, Luiz Capitulino <lcapitulino@redhat.com>

On 03/11/2010 03:25 PM, Paolo Bonzini wrote:
> On 03/11/2010 01:57 PM, Paul Brook wrote:
>> +struct QEMUNotifier
>> >  +{
>> >  +    void (*notify)(QEMUNotifier *notifier);
>> >  +};
>>
>> I suggest combining this with QEMUBH.
>
> I didn't understand this suggestion exactly, but I think it's related 
> that I didn't understand the advantage of making QEMUNotifier a 
> struct.  Instead of using container_of, reusing QEMUBHFunc (renamed to 
> QEMUCallbackFunc maybe?) in QEMUNotifierNode like this:
>
>     struct QEMUNotifierNode {
>         QEMUCallbackFunc notify;
>         void *opaque;
>         QTAILQ_ENTRY(QEMUNotifierNode) node;
>     };
>
>     void qemu_notifier_list_init(QEMUNotifierList *list);
>
>     struct QEMUNotifierNode *
>     qemu_notifier_list_add(QEMUNotifierList *list,
>                            QEMUCallbackFunc notify, void *opaque);
>
>     void qemu_notifier_list_remove(QEMUNotifierList *list,
>                                    QEMUNotifierNode *notifier);
>
>     void qemu_notifier_list_notify(QEMUNotifierList *list);
>
> seems cleaner.  You would place the QEMUNotifierNode in VncState in 
> order to do the removal later.
>
>

I disagree.  container_of() is both a little more type safe, and removes 
the need for an extra pointer and memory object.

The caller will almost always have an object in which to embed the 
notifier, best to make use of it.

-- 
error compiling committee.c: too many arguments to function