Asynchronus serial port

[Wolfgang Walter]

Am Donnerstag, 3. September 2009 schrieb Mike Kaplinskiy:
> On Wed, Sep 2, 2009 at 7:31 PM, Fenixk19<fenixk19 at mail.ru> wrote:
> > Hello! I've already post the
> > bug(http://bugs.winehq.org/show_bug.cgi?id=19713) on this subject, but i
> > need more help. So I've decided to write here.
> > There is a problem in wine. When I use asynchronous serial port read,
> > data never comes. Event, caused by select comes. But operation status
> > stays pending, and i can't do anything to this serial port anymore. In
> > windows it never get pending, and port can be accessed just after data
> > arrival. Seems to be wineserver problem, but i don't know, where to look
> > at. What code respond for asynchronous serial port in wineserver?
> > Alexander.
> > P.S. Test program attached.
>
> Hi,
>
> Alexandre would be the guy to talk to about wineserver-related things.
> Sadly he's off on a long weekend. Does the attached patch help solve
> the problem?

Isn't setting commio->iosb->u.Status racy?

commio->iosb may be set from wait_for_event() which is called by an extra 
thread or by io_control().

Couldn't it happen that

	wait_on starts the thread
	wait_for_event sets the commio->iosb->u.Status to STATUS_SUCCESS
	wait_on returns to io_control STATUS_PENDING
	io_control overwrites commio->iosb->u.Status with STATUS_PENDING

I think io_control() should set commio->iosb->u.Status to STATUS_PENDING 
before calling wait_on(). After wait_on() io_control() should not set 
commio->iosb->u.Status if wait_on() returns STATUS_PENDING. Here the idea:

------------------
    case IOCTL_SERIAL_WAIT_ON_MASK:
         if (lpOutBuffer && nOutBufferSize == sizeof(DWORD))
         {
             piosb->u.Status = STATUS_PENDING;
             piosb->Information = sz;
             if (!(status = wait_on(hDevice, fd, hEvent, piosb, lpOutBuffer)))
                 sz = sizeof(DWORD);
             else if (status == STATUS_PENDING)
                 return status;
         }
         else
             status = STATUS_INVALID_PARAMETER;
         break;
-------------------


Regards,
-- 
Wolfgang Walter
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