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

[Marc Hartmayer]

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.

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

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