fs/xfs/linux-2.6/sema.h

   1 /*
   2  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_SUPPORT_SEMA_H__
  19 #define __XFS_SUPPORT_SEMA_H__
  20
  21 #include <linux/time.h>
  22 #include <linux/wait.h>
  23 #include <asm/atomic.h>
  24 #include <asm/semaphore.h>
  25
  26 /*
  27  * sema_t structure just maps to struct semaphore in Linux kernel.
  28  */
  29
  30 typedef struct semaphore sema_t;
  31
  32 #define init_sema(sp, val, c, d)        sema_init(sp, val)
  33 #define initsema(sp, val)               sema_init(sp, val)
  34 #define initnsema(sp, val, name)        sema_init(sp, val)
  35 #define psema(sp, b)                    down(sp)
  36 #define vsema(sp)                       up(sp)
  37 #define valusema(sp)                    (atomic_read(&(sp)->count))
  38 #define freesema(sema)
  39
  40 /*
  41  * Map cpsema (try to get the sema) to down_trylock. We need to switch
  42  * the return values since cpsema returns 1 (acquired) 0 (failed) and
  43  * down_trylock returns the reverse 0 (acquired) 1 (failed).
  44  */
  45
  46 #define cpsema(sp)                      (down_trylock(sp) ? 0 : 1)
  47
  48 /*
  49  * Didn't do cvsema(sp). Not sure how to map this to up/down/...
  50  * It does a vsema if the values is < 0 other wise nothing.
  51  */
  52
  53 #endif /* __XFS_SUPPORT_SEMA_H__ */