Re: [Qemu-devel] [PATCH 10/10] aio-win32: add support for sockets

[TeLeMan]

On Sat, Sep 13, 2014 at 6:33 PM, Paolo Bonzini <address@hidden> wrote:
> Il 13/09/2014 04:22, TeLeMan ha scritto:
>> On Fri, Sep 12, 2014 at 6:05 PM, Paolo Bonzini <address@hidden> wrote:
>>> Il 12/09/2014 03:39, TeLeMan ha scritto:
>>>> On Wed, Jul 9, 2014 at 5:53 PM, Paolo Bonzini <address@hidden> wrote:
>>>>> diff --git a/aio-win32.c b/aio-win32.c
>>>>> index 4542270..61e3d2d 100644
>>>>> --- a/aio-win32.c
>>>>> +++ b/aio-win32.c
>>>>> +    bool was_dispatching, progress, have_select_revents, first;
>>>> have_select_revents has no initial value.
>>>
>>> Good catch here...
>>>
>>>>
>>>>> @@ -183,6 +318,7 @@ bool aio_poll(AioContext *ctx, bool blocking)
>>>>>
>>>>>      /* wait until next event */
>>>>>      while (count > 0) {
>>>>> +        HANDLE event;
>>>>>          int ret;
>>>>>
>>>>>          timeout = blocking
>>>>> @@ -196,13 +332,17 @@ bool aio_poll(AioContext *ctx, bool blocking)
>>>>>          first = false;
>>>>>
>>>>>          /* if we have any signaled events, dispatch event */
>>>>> -        if ((DWORD) (ret - WAIT_OBJECT_0) >= count) {
>>>>> +        event = NULL;
>>>>> +        if ((DWORD) (ret - WAIT_OBJECT_0) < count) {
>>>>> +            event = events[ret - WAIT_OBJECT_0];
>>>>> +        } else if (!have_select_revents) {
>>>>
>>>> when (ret - WAIT_OBJECT_0) >= count and have_select_revents is true,
>>>> the following events[ret - WAIT_OBJECT_0] will be overflowed.
>>>
>>> ... this instead is not a problem, ret - WAIT_OBJECT_0 can be at most
>>> equal to count, and events[] is declared with MAXIMUM_WAIT_OBJECTS + 1
>>> places.  So the
>>>
>>>         events[ret - WAIT_OBJECT_0] = events[--count];
>>>
>>> is equal to
>>>
>>>         events[count] = events[count - 1];
>>>         --count;
>>>
>>> and this is harmless.
>>
>> WAIT_ABANDONED_0 & WAIT_TIMEOUT & WAIT_FAILED are larger than
>> MAXIMUM_WAIT_OBJECTS.
>
> WAIT_ABANDONED_0 and WAIT_FAILED cannot happen, but you're right about
> WAIT_TIMEOUT.  Are you going to send a patch?

No, because I was rejected to submit the patch, so I just report the issues.

> Paolo
>
>>> Paolo
>>>
>>>>>              break;
>>>>>          }
>>>>>
>>>>> +        have_select_revents = false;
>>>>>          blocking = false;
>>>>>
>>>>> -        progress |= aio_dispatch_handlers(ctx, events[ret - 
>>>>> WAIT_OBJECT_0]);
>>>>> +        progress |= aio_dispatch_handlers(ctx, event);
>>>>>
>>>>>          /* Try again, but only call each handler once.  */
>>>>>          events[ret - WAIT_OBJECT_0] = events[--count];
>>>
>>
>>
>