reactos/ntoskrnl/ex/fmutex.c

   1 /* $Id: fmutex.c,v 1.8 2000/12/23 02:37:39 dwelch Exp $
   2  *
   3  * COPYRIGHT:       See COPYING in the top level directory
   4  * PROJECT:         ReactOS kernel
   5  * FILE:            ntoskrnl/ex/fmutex.c
   6  * PURPOSE:         Implements fast mutexes
   7  * PROGRAMMER:      David Welch (welch@cwcom.net)
   8  * UPDATE HISTORY:
   9  *                  Created 22/05/98
  10  */
  11
  12 /* INCLUDES *****************************************************************/
  13
  14 #include <ddk/ntddk.h>
  15
  16 #include <internal/debug.h>
  17
  18
  19 /* FUNCTIONS *****************************************************************/
  20
  21 VOID FASTCALL EXPORTED
  22 ExAcquireFastMutexUnsafe (PFAST_MUTEX   FastMutex)
  23 {
  24    if (InterlockedDecrement(&FastMutex->Count) == 0)
  25      {
  26         return;
  27      }
  28    FastMutex->Contention++;
  29    KeWaitForSingleObject(&FastMutex->Event,
  30                          Executive,
  31                          KernelMode,
  32                          FALSE,
  33                          NULL);
  34    FastMutex->Owner = KeGetCurrentThread();
  35 }
  36
  37 VOID FASTCALL EXPORTED
  38 ExReleaseFastMutexUnsafe (PFAST_MUTEX   FastMutex)
  39 {
  40    assert(FastMutex->Owner == KeGetCurrentThread());
  41    if (InterlockedIncrement(&FastMutex->Count) <= 0)
  42      {
  43         return;
  44      }
  45    FastMutex->Owner = NULL;
  46    KeSetEvent(&FastMutex->Event, 0, FALSE);
  47 }
  48
  49 /* EOF */