[ros-dev] Re: [ros-diffs] [ion] 19352: - Reimplement Fast Mutex implementation in HAL/NT to be compatible with the real implementation. (Fast Mutex needs to raise IRQL).

[Hartmut Birr]

ion(a)svn.reactos.com wrote:
>   - Reimplement Fast Mutex implementation in HAL/NT to
> be compatible with the real implementation. (Fast Mutex needs to raise IRQL).
>  - Implement ExEnterCriticalRegionAndAcquireFastMutexUnsafe and
> ExReleaseFastMutexUnsafeAndLeaveCriticalRegion.
>  - Make win32k use those two new functions so that it can continue running at
> PASSIVE_LEVEL.
>  - Remove CcBrokenMutex and use the new APIs instead.
>  - Implement and export ntoskrnl version of Fast Mutex
>  - Update headers for new fast-mutex definition and API exports.
>  - Fix RemoveEntryList in NDK.
>  - Add exfuncs.h to NDK.
>  - Fix path in mmtypes.h in NDK to be compatible to how it shoudl be included.
>  *Modified: trunk/reactos/hal/halx86/generic/fmutex.c*
>  --- trunk/reactos/hal/halx86/generic/fmutex.c	2005-11-19 21:07:25 UTC (rev 19351)
>  +++ trunk/reactos/hal/halx86/generic/fmutex.c	2005-11-19 22:13:35 UTC (rev 19352)
>  +VOID
>  +FASTCALL
>  +ExAcquireFastMutex(PFAST_MUTEX FastMutex)
>    
>   {
>    
>  -   KeEnterCriticalRegion();
>  -   ExAcquireFastMutexUnsafe(FastMutex);
>    
>  +    KIRQL OldIrql;
>  +
>  +    /* Raise IRQL to APC */
>  +    OldIrql = KfRaiseIrql(APC_LEVEL);
>  +
>  +    /* Decrease the count */
>  +    if (InterlockedDecrement(&FastMutex->Count))
>  +    {
>  +        /* Someone is still holding it, use slow path */
>  +        FastMutex->Contention++;
>  +        KeWaitForSingleObject(&FastMutex->Gate,
>  +                              WrExecutive,
>  +                              WaitAny,
>  +                              FALSE,
>  +                              NULL);
>  +    }
>  +
>  +    /* Set the owner and IRQL */
>  +    FastMutex->Owner = KeGetCurrentThread();
>  +    FastMutex->OldIrql = OldIrql;
>    
>   }
>     
Hi,

this piece of  code is wrong. If we terminating a thread, which waits on
something, we do unblock the thread. The thread must check, if it got
the lock, if not it must wait again.

- Hartmut