Re: [Qemu-devel] [RFC][PATCH 01/16 v6] monitor: introduce qemu_suspend_monitor()/qemu_resume_monitor()

[Wen Congyang <wency@cn.fujitsu.com>]

At 02/15/2012 09:01 PM, Luiz Capitulino Wrote:
> On Wed, 15 Feb 2012 09:51:04 +0100
> Jan Kiszka <jan.kiszka@siemens.com> wrote:
> 
>> On 2012-02-15 03:54, Wen Congyang wrote:
>>> At 02/15/2012 12:19 AM, Jan Kiszka Wrote:
>>>> On 2012-02-09 04:19, Wen Congyang wrote:
>>>>> Sync command needs these two APIs to suspend/resume monitor.
>>>>>
>>>>> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
>>>>> ---
>>>>>  monitor.c |   27 +++++++++++++++++++++++++++
>>>>>  monitor.h |    2 ++
>>>>>  2 files changed, 29 insertions(+), 0 deletions(-)
>>>>>
>>>>> diff --git a/monitor.c b/monitor.c
>>>>> index 11639b1..7e72739 100644
>>>>> --- a/monitor.c
>>>>> +++ b/monitor.c
>>>>> @@ -4442,6 +4442,26 @@ static void monitor_command_cb(Monitor *mon, const char *cmdline, void *opaque)
>>>>>      monitor_resume(mon);
>>>>>  }
>>>>>  
>>>>> +int qemu_suspend_monitor(const char *fmt, ...)
>>>>> +{
>>>>> +    int ret;
>>>>> +
>>>>> +    if (cur_mon) {
>>>>> +        ret = monitor_suspend(cur_mon);
>>>>> +    } else {
>>>>> +        ret = -ENOTTY;
>>>>> +    }
>>>>> +
>>>>> +    if (ret < 0 && fmt) {
>>>>> +        va_list ap;
>>>>> +        va_start(ap, fmt);
>>>>> +        monitor_vprintf(cur_mon, fmt, ap);
>>>>> +        va_end(ap);
>>>>> +    }
>>>>> +
>>>>> +    return ret;
>>>>> +}
>>>>> +
>>>>>  int monitor_suspend(Monitor *mon)
>>>>>  {
>>>>>      if (!mon->rs)
>>>>> @@ -4450,6 +4470,13 @@ int monitor_suspend(Monitor *mon)
>>>>>      return 0;
>>>>>  }
>>>>>  
>>>>> +void qemu_resume_monitor(void)
>>>>> +{
>>>>> +    if (cur_mon) {
>>>>> +        monitor_resume(cur_mon);
>>>>> +    }
>>>>> +}
>>>>> +
>>>>>  void monitor_resume(Monitor *mon)
>>>>>  {
>>>>>      if (!mon->rs)
>>>>> diff --git a/monitor.h b/monitor.h
>>>>> index 58109af..60a1e17 100644
>>>>> --- a/monitor.h
>>>>> +++ b/monitor.h
>>>>> @@ -46,7 +46,9 @@ int monitor_cur_is_qmp(void);
>>>>>  void monitor_protocol_event(MonitorEvent event, QObject *data);
>>>>>  void monitor_init(CharDriverState *chr, int flags);
>>>>>  
>>>>> +int qemu_suspend_monitor(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>>>>>  int monitor_suspend(Monitor *mon);
>>>>> +void qemu_resume_monitor(void);
>>>>>  void monitor_resume(Monitor *mon);
>>>>>  
>>>>>  int monitor_read_bdrv_key_start(Monitor *mon, BlockDriverState *bs,
>>>>
>>>> I don't see any added value in this API, specifically as it is built on
>>>> top of cur_mon. Just use the existing services like the migration code
>>>> does. If you properly pass down the monitor reference from the command
>>>> to the suspend and store what monitor you suspended, all should be fine.
>>>
>>> This API is like qemu_get_fd() which is not merged into upstream qemu.
>>> I need this API because I cannot use monitor in qapi command.
>>
>> OK, then I need to comment on that approach. QMP looks flawed here.
>> Either you have a need for a Monitor object (or a generic HMP/QMP
>> context), then you also have a handle. Or your don't, then you do not
>> need monitor suspend/resume or get_fd as well.
> 
> The getfd one is explained in the other thread, but suspend/resume should
> be done from HMP only.

I have read the newest migration code. I will change the code like that and
remove these two APIs.

Please ignore this patch

Thanks
Wen Congyang

> 
> PS: Haven't reviewed this series yet.
>