3 * Copyright (C) 1998, 1999, 2000, 2001 ReactOS Team
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.
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.
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.
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.
30 /* INCLUDES *****************************************************************/
32 #include <ddk/ntddk.h>
34 #include <internal/debug.h>
36 /* FUNCTIONS *****************************************************************/
39 ExAcquireFastMutexUnsafe(PFAST_MUTEX FastMutex)
41 assert(FastMutex->Owner != KeGetCurrentThread());
42 InterlockedIncrement(&FastMutex->Contention);
43 while (InterlockedExchange(&FastMutex->Count, 0) == 0)
45 KeWaitForSingleObject(&FastMutex->Event,
51 InterlockedDecrement(&FastMutex->Contention);
52 FastMutex->Owner = KeGetCurrentThread();
56 ExReleaseFastMutexUnsafe(PFAST_MUTEX FastMutex)
58 assert(FastMutex->Owner == KeGetCurrentThread());
59 FastMutex->Owner = NULL;
60 if (FastMutex->Contention > 0)
62 KeSetEvent(&FastMutex->Event, 0, FALSE);
64 InterlockedExchange(&FastMutex->Count, 1);