tor 2007-10-04 klockan 11:11 +0200 skrev Mats Kindahl:
> Hi Magnus!
>
> Patch approved. I checked that the recursion count really is increased.
Good, I did that in the debugger. Couldn't really figure out how to
implement that assert you mentioned to be atomic. Or should I do it only
only as a test?
The scary thing is that we really are looking into a struct defined by
MS.
>
> Just my few cents,
> Mats Kindahl
>
> msvensson@stripped wrote:
> > Below is the list of changes that have just been committed into a local
> > 5.0 repository of msvensson. When msvensson does a push these changes will
> > be propagated to the main repository and, within 24 hours after the
> > push, to the public repository.
> > For information on how to access the public repository
> > see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html
> >
> > ChangeSet@stripped, 2007-10-03 21:38:32+02:00, msvensson@stripped +2 -0
> > Bug#30992 Wrong implementation of pthread_mutex_trylock()
> > It's not possible to use WaitForSingleObject to wait
> > on a CRITICAL_SECTION, instead use the TryEnterCriticalSection function.
> > - if "mutex" was already taken => return EBUSY
> > - if "mutex" was aquired => return 0
> >
> > include/config-win.h@stripped, 2007-10-03 21:38:30+02:00,
> msvensson@stripped +3 -0
> > Make windows.h define TryEnterCriticalSection
> >
> > mysys/my_winthread.c@stripped, 2007-10-03 21:38:30+02:00,
> msvensson@stripped +10 -12
> > Use the TryEnterCriticalSection function to implement pthread_mutex_trylock
> > Prevent recursive behaviour by looking at the RecursionCount variable
> > in the CRITICAL_SECTION struct and return EBUSY from function if
> > the mutex was already locked once.
> >
> > diff -Nrup a/include/config-win.h b/include/config-win.h
> > --- a/include/config-win.h 2007-03-28 23:00:25 +02:00
> > +++ b/include/config-win.h 2007-10-03 21:38:30 +02:00
> > @@ -19,6 +19,9 @@
> > /* We have to do this define before including windows.h to get the AWE API
> > functions */
> > #define _WIN32_WINNT 0x0500
> > +#else
> > +/* Get NT 4.0 functions */
> > +#define _WIN32_WINNT 0x0400
> > #endif
> >
> > #if defined(_MSC_VER) && _MSC_VER >= 1400
> > diff -Nrup a/mysys/my_winthread.c b/mysys/my_winthread.c
> > --- a/mysys/my_winthread.c 2007-10-01 15:11:12 +02:00
> > +++ b/mysys/my_winthread.c 2007-10-03 21:38:30 +02:00
> > @@ -40,30 +40,28 @@ void win_pthread_init(void)
> > pthread_mutex_init(&THR_LOCK_thread,MY_MUTEX_INIT_FAST);
> > }
> >
> > +
> > /**
> > Adapter to @c pthread_mutex_trylock()
> >
> > @retval 0 Mutex was acquired
> > @retval EBUSY Mutex was already locked by a thread
> > - @retval EINVAL Mutex could not be acquired due to other error
> > */
> > int
> > win_pthread_mutex_trylock(pthread_mutex_t *mutex)
> > {
> > - switch (WaitForSingleObject(mutex, 0)) {
> > - case WAIT_TIMEOUT:
> > - return EBUSY;
> > -
> > - default:
> > - case WAIT_FAILURE:
> > - return EINVAL;
> > -
> > - case WAIT_OBJECT_0:
> > - case WAIT_ABANDONED: /* The mutex was acquired because it was
> > - * abandoned */
> > + if (TryEnterCriticalSection(mutex))
> > + {
> > + /* Don't allow recursive lock */
> > + if (mutex->RecursionCount > 1){
> > + LeaveCriticalSection(mutex);
> > + return EBUSY;
> > + }
> > return 0;
> > }
> > + return EBUSY;
> > }
> > +
> >
> > /*
> > ** We have tried to use '_beginthreadex' instead of '_beginthread' here
> >
> >
>
>
--
Magnus Svensson
Senior Software Engineer
msvensson@stripped
+46709164491
