reactos/ntoskrnl/ex/fmutex.c

   1 /*
   2  *  ReactOS kernel
   3  *  Copyright (C) 1998, 1999, 2000, 2001 ReactOS Team
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19 /* $Id: fmutex.c,v 1.10 2001/06/20 12:57:32 ekohl Exp $
  20  *
  21  * PROJECT:         ReactOS kernel
  22  * FILE:            ntoskrnl/ex/fmutex.c
  23  * PURPOSE:         Implements fast mutexes
  24  * PROGRAMMER:      David Welch (welch@cwcom.net)
  25  * PORTABILITY:     Checked.
  26  * UPDATE HISTORY:
  27  *                  Created 22/05/98
  28  */
  29
  30 /* INCLUDES *****************************************************************/
  31
  32 #include <ddk/ntddk.h>
  33
  34 #include <internal/debug.h>
  35
  36
  37 /* FUNCTIONS *****************************************************************/
  38
  39 VOID FASTCALL
  40 ExAcquireFastMutexUnsafe(PFAST_MUTEX FastMutex)
  41 {
  42    if (InterlockedDecrement(&FastMutex->Count) == 0)
  43      {
  44         return;
  45      }
  46    FastMutex->Contention++;
  47    KeWaitForSingleObject(&FastMutex->Event,
  48                          Executive,
  49                          KernelMode,
  50                          FALSE,
  51                          NULL);
  52    FastMutex->Owner = KeGetCurrentThread();
  53 }
  54
  55 VOID FASTCALL
  56 ExReleaseFastMutexUnsafe(PFAST_MUTEX FastMutex)
  57 {
  58    assert(FastMutex->Owner == KeGetCurrentThread());
  59    if (InterlockedIncrement(&FastMutex->Count) <= 0)
  60      {
  61         return;
  62      }
  63    FastMutex->Owner = NULL;
  64    KeSetEvent(&FastMutex->Event, 0, FALSE);
  65 }
  66
  67 /* EOF */