[libvirt] [PATCH 02/20] remote: Don't hard code the feature VIR_DRV_FEATURE_REMOTE_CLOSE_CALLBACK as available

[Marc Hartmayer]

On Tue, Apr 03, 2018 at 02:05 PM +0200, "Daniel P. Berrangé" <berrange at redhat.com> wrote:
> On Tue, Apr 03, 2018 at 01:46:13PM +0200, Marc Hartmayer wrote:
>> On Wed, Mar 21, 2018 at 07:57 AM +0100, Marc Hartmayer <mhartmay at linux.vnet.ibm.com> wrote:
>> > On Mon, Mar 19, 2018 at 04:06 PM +0100, "Daniel P. Berrangé" <berrange at redhat.com> wrote:
>> >> On Thu, Mar 08, 2018 at 01:20:25PM +0100, Marc Hartmayer wrote:
>> >>> Don't assume that the feature VIR_DRV_FEATURE_REMOTE_CLOSE_CALLBACK is
>> >>> available for every driver used for the connection.
>> >>
>> >> The very definition of the virConnectRegisterCloseCallback() API is that
>> >> it will always succeed.   What varies is that some driver connections
>> >> may never fail and so the close callback will never be invoked. The actual
>> >> registration of the callback will always succeed regardless of which driver
>> >> is in use. So it is correct to report the VIR_DRV_FEATURE_REMOTE_CLOSE_CALLBACK
>> >> as always supported regardless of driver.
>> >
>> > Okay. So how can we deal with the situation in patch 18 if we cannot
>> > differentiate between 'callback was “really” registered' and only the
>> > call was 'successful'? If it’s not really registered nobody will free
>> > the callback data. This was also the cause for the fix: ce35122cfe:
>> > "daemon: fixup refcounting in close callback handling".
>> >
>> > Thanks in advance.
>>
>> Polite ping.
>
> If conn->driver->connectRegisterCloseCallback is NULL, then the
> virConnectRegisterCloseCallback()  method should immediately
> call  freecb(opaque).

Thanks! I’ll send a v2.

>
>
> Regards,
> Daniel
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Beste Grüße / Kind regards
   Marc Hartmayer

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