[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 at 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