Hi Magnus!
Patch approved. I checked that the recursion count really is increased.
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
>
>
--
Mats Kindahl
Lead Software Developer
Replication Team
MySQL AB, www.mysql.com
