Return to sema.h CVS log

Up to [Development] / xfs-linux / linux-2.6

Kill direct access to ->count in valusema(); all we ever use it for is check
if semaphore is actually locked, which can be trivially done in portable way.
Code gets more reabable, while we are at it...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge of xfs-linux-melb:xfs-kern:26274a by kenmcd.

  Kill direct access to ->count in valusema(); all we ever use it for is check
  if semaphore is actually locked, which can be trivially done in portable way.

/*
 * 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 init_sema(sp, val, c, d)	sema_init(sp, val)
#define initsema(sp, val)		sema_init(sp, val)
#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__ */