reactos/ntoskrnl/ex/fmutex.c

   1 /* $Id: fmutex.c,v 1.6 2000/06/09 20:02:59 ekohl 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
  22 FASTCALL
  23 EXPORTED
  24 ExAcquireFastMutexUnsafe (
  25         PFAST_MUTEX     FastMutex
  26         )
  27 {
  28    if (InterlockedDecrement(&(FastMutex->Count))==0)
  29      {
  30         return;
  31      }
  32    FastMutex->Contention++;
  33    KeWaitForSingleObject(&(FastMutex->Event),
  34                          Executive,
  35                          KernelMode,
  36                          FALSE,
  37                          NULL);
  38    FastMutex->Owner=KeGetCurrentThread();
  39 }
  40
  41 VOID
  42 FASTCALL
  43 EXPORTED
  44 ExReleaseFastMutexUnsafe (
  45         PFAST_MUTEX     FastMutex
  46         )
  47 {
  48    assert(FastMutex->Owner == KeGetCurrentThread());
  49    FastMutex->Owner=NULL;
  50    if (InterlockedIncrement(&(FastMutex->Count))<=0)
  51      {
  52         return;
  53      }
  54    KeSetEvent(&(FastMutex->Event),0,FALSE);
  55 }
  56
  57 /* EOF */