Re: [PATCH v2 05/15] libxl: change libxl__ao_device_remove to libxl__ao_device

[Roger Pau Monne <roger.pau@citrix.com>]

Ian Jackson wrote:
> Roger Pau Monne writes ("[PATCH v2 05/15] libxl: change libxl__ao_device_remove to libxl__ao_device"):
>> Introduce a new structure to track state of device backends, that will
>> be used in following patches on this series.
>>
>> This structure if used for both device creation and device
>> destruction and removes libxl__ao_device_remove.
>
>> diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
>> index ae5527b..b62110a 100644
>> --- a/tools/libxl/libxl_internal.h
>> +++ b/tools/libxl/libxl_internal.h
>> @@ -1802,6 +1795,44 @@ _hidden void libxl__bootloader_init(libxl__bootloader_state *bl);
> ...
>> +/* Device AO operations */
>>
>> -typedef struct {
>> -    libxl__ao *ao;
>> -    libxl__ev_devstate ds;
>> -} libxl__ao_device_remove;
>> +void libxl__init_ao_device(libxl__ao_device *aorm, libxl__ao *ao,
>> +                           libxl__ao_device **base)
>> +{
>> +    aorm->ao = ao;
>> +    aorm->active = 1;
>> +    aorm->rc = 0;
>> +    aorm->base = base;
>> +}
>
> I think a function "init" should set "active" to 0, surely ?
> Since the operation has not in fact been started.  So perhaps this
> should just be a memset.

Forget to answer this, we cannot use active = 0 at init because in the 
hypothetical case that a device add/remove finished before queuing all 
the others (so the others would be active == 0) it would mark the ao as 
complete, since it would see all other operations as finished.