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.
19 /* $Id: fmutex.c,v 1.19 2003/07/10 06:27:13 royce Exp $
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 *****************************************************************/
42 ExAcquireFastMutexUnsafe(PFAST_MUTEX FastMutex
)
44 assert(FastMutex
->Owner
!= KeGetCurrentThread());
45 InterlockedIncrement((LONG
*)&FastMutex
->Contention
);
46 while (InterlockedExchange(&FastMutex
->Count
, 0) == 0)
48 KeWaitForSingleObject(&FastMutex
->Event
,
54 InterlockedDecrement((LONG
*)&FastMutex
->Contention
);
55 FastMutex
->Owner
= KeGetCurrentThread();
62 ExReleaseFastMutexUnsafe(PFAST_MUTEX FastMutex
)
64 assert(FastMutex
->Owner
== KeGetCurrentThread());
65 FastMutex
->Owner
= NULL
;
66 if (FastMutex
->Contention
> 0)
68 KeSetEvent(&FastMutex
->Event
, 0, FALSE
);
70 InterlockedExchange(&FastMutex
->Count
, 1);