reactos/ntoskrnl/ex/fmutex.c

   1 /* $Id$
   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  *
   8  * PROGRAMMERS:     David Welch (welch@cwcom.net)
   9  */
  10
  11 /* INCLUDES *****************************************************************/
  12
  13 #include <ntoskrnl.h>
  14 #include <internal/debug.h>
  15
  16 /* FUNCTIONS *****************************************************************/
  17
  18 /*
  19  * @implemented
  20  */
  21 VOID FASTCALL
  22 ExAcquireFastMutexUnsafe(PFAST_MUTEX FastMutex)
  23 {
  24   ASSERT(FastMutex->Owner != KeGetCurrentThread());
  25   InterlockedIncrementUL(&FastMutex->Contention);
  26   while (InterlockedExchange(&FastMutex->Count, 0) == 0)
  27      {
  28        KeWaitForSingleObject(&FastMutex->Event,
  29                              Executive,
  30                              KernelMode,
  31                              FALSE,
  32                              NULL);
  33      }
  34   InterlockedDecrementUL(&FastMutex->Contention);
  35   FastMutex->Owner = KeGetCurrentThread();
  36 }
  37
  38 /*
  39  * @implemented
  40  */
  41 VOID FASTCALL
  42 ExReleaseFastMutexUnsafe(PFAST_MUTEX FastMutex)
  43 {
  44   ASSERT(FastMutex->Owner == KeGetCurrentThread());
  45   FastMutex->Owner = NULL;
  46   InterlockedExchange(&FastMutex->Count, 1);
  47   if (FastMutex->Contention > 0)
  48     {
  49       KeSetEvent(&FastMutex->Event, 0, FALSE);
  50     }
  51 }
  52
  53 /* EOF */