Re: [Qemu-devel] [PATCH 14/32] qmp: Always free QMPRequest with qmp_request_free()

[Markus Armbruster]

Eric Blake <address@hidden> writes:

> On 07/02/2018 11:22 AM, Markus Armbruster wrote:
>> monitor_qmp_dispatch_one() frees a QMPRequest manually, because it
>> needs to keep a reference to ->id.  Premature optimization.  Take an
>> additional reference so we can use qmp_request_free().
>>
>> Signed-off-by: Markus Armbruster <address@hidden>
>> ---
>>   monitor.c | 6 ++----
>>   1 file changed, 2 insertions(+), 4 deletions(-)
>>
>
> Reviewed-by: Eric Blake <address@hidden>
>
>> diff --git a/monitor.c b/monitor.c
>> index 10991757f6..94f5660c3c 100644
>> --- a/monitor.c
>> +++ b/monitor.c
>> @@ -4181,8 +4181,6 @@ static void monitor_qmp_dispatch_one(QMPRequest 
>> *req_obj)
>>       id = req_obj->id;
>>       need_resume = req_obj->need_resume;
>>   -    g_free(req_obj);
>> -
>>       old_mon = cur_mon;
>>       cur_mon = mon;
>>   @@ -4191,14 +4189,14 @@ static void
>> monitor_qmp_dispatch_one(QMPRequest *req_obj)
>>       cur_mon = old_mon;
>>         /* Respond if necessary */
>> -    monitor_qmp_respond(mon, rsp, NULL, id);
>> +    monitor_qmp_respond(mon, rsp, NULL, qobject_ref(id));
>
> This requires qobject_ref(NULL) to work (I thought at one point we
> were considering requiring it to be a non-NULL argument, but right now
> it looks like we are safe).

[PATCH v6 5/5] qobject: modify qobject_ref() to assert on NULL
Message-Id: <address@hidden>

I didn't merge it back then because I lacked the time to convince myself
all users of qobject_ref() the patch doesn't guard cannot pass null, and
also because I wasn't sure requiring qobject_ref()'s argument to be
non-null improves legibility of the code.  Right now we got bigger fish
to fry.