fs/xfs/linux-2.6/sema.h

   1 /*
   2  * Copyright (c) 2000-2002 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32 #ifndef __XFS_SUPPORT_SEMA_H__
  33 #define __XFS_SUPPORT_SEMA_H__
  34
  35 #include <linux/time.h>
  36 #include <linux/wait.h>
  37 #include <asm/atomic.h>
  38 #include <asm/semaphore.h>
  39
  40 /*
  41  * sema_t structure just maps to struct semaphore in Linux kernel.
  42  */
  43
  44 typedef struct semaphore sema_t;
  45
  46 #define init_sema(sp, val, c, d)        sema_init(sp, val)
  47 #define initsema(sp, val)               sema_init(sp, val)
  48 #define initnsema(sp, val, name)        sema_init(sp, val)
  49 #define psema(sp, b)                    down(sp)
  50 #define vsema(sp)                       up(sp)
  51 #define valusema(sp)                    (atomic_read(&(sp)->count))
  52 #define freesema(sema)
  53
  54 /*
  55  * Map cpsema (try to get the sema) to down_trylock. We need to switch
  56  * the return values since cpsema returns 1 (acquired) 0 (failed) and
  57  * down_trylock returns the reverse 0 (acquired) 1 (failed).
  58  */
  59
  60 #define cpsema(sp)                      (down_trylock(sp) ? 0 : 1)
  61
  62 /*
  63  * Didn't do cvsema(sp). Not sure how to map this to up/down/...
  64  * It does a vsema if the values is < 0 other wise nothing.
  65  */
  66
  67 #endif /* __XFS_SUPPORT_SEMA_H__ */