Re: [Qemu-devel] [PATCH] qom: Make object_child_foreach safe for objects removal

[Alexey Kardashevskiy]

On 07/14/2014 06:14 PM, Paolo Bonzini wrote:
> Il 13/07/2014 16:41, Alexey Kardashevskiy ha scritto:
>> Current object_child_foreach() uses QTAILQ_FOREACH() to walk
>> through children and that makes children removal from the callback
>> impossible.
>>
>> This makes object_child_foreach() use QTAILQ_FOREACH_SAFE().
>>
>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>> ---
>>
>> The problem I am trying to solve is:
>> there is a PHB with multiple DMA windows a.k.a. sPAPRTCETable's which are
>> QOM children of PHB. One of RTAS functions is "reset" which is supposed to
>> remove all windows (now just one) except the default one.
>>
>> I could call QTAILQ_FOREACH_SAFE in sPAPR PHB code but
>> object_property_is_child()
>> is static and we probably do not want to make it public.
>>
>>
>> ---
>>  qom/object.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/qom/object.c b/qom/object.c
>> index 0e8267b..4a814dc 100644
>> --- a/qom/object.c
>> +++ b/qom/object.c
>> @@ -678,10 +678,10 @@ void object_class_foreach(void (*fn)(ObjectClass
>> *klass, void *opaque),
>>  int object_child_foreach(Object *obj, int (*fn)(Object *child, void
>> *opaque),
>>                           void *opaque)
>>  {
>> -    ObjectProperty *prop;
>> +    ObjectProperty *prop, *next;
>>      int ret = 0;
>>
>> -    QTAILQ_FOREACH(prop, &obj->properties, node) {
>> +    QTAILQ_FOREACH_SAFE(prop, &obj->properties, node, next) {
>>          if (object_property_is_child(prop)) {
>>              ret = fn(prop->opaque, opaque);
>>              if (ret != 0) {
>>
> 
> The patch is certainly okay, do you need it in 2.1?


Nope, I will need it for dynamic DMA windows (VFIO, PPC) which are not for
2.1 for sure.



-- 
Alexey