linux/fs/xfs/linux-2.6/sema.h

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/*
* Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef __XFS_SUPPORT_SEMA_H__
#define __XFS_SUPPORT_SEMA_H__
#include <linux/time.h>
#include <linux/wait.h>
#include <asm/atomic.h>
#include <asm/semaphore.h>
/*
* sema_t structure just maps to struct semaphore in Linux kernel.
*/
typedef struct semaphore sema_t;
#define initnsema(sp, val, name) sema_init(sp, val)
#define psema(sp, b) down(sp)
#define vsema(sp) up(sp)
#define freesema(sema) do { } while (0)
static inline int issemalocked(sema_t *sp)
{
return down_trylock(sp) || (up(sp), 0);
}
/*
* Map cpsema (try to get the sema) to down_trylock. We need to switch
* the return values since cpsema returns 1 (acquired) 0 (failed) and
* down_trylock returns the reverse 0 (acquired) 1 (failed).
*/
static inline int cpsema(sema_t *sp)
{
return down_trylock(sp) ? 0 : 1;
}
#endif /* __XFS_SUPPORT_SEMA_H__ */