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/*
* Copyright (c) 2000 Silicon Graphics, Inc. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 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.
*
* Further, this software is distributed without any warranty that it is
* free of the rightful claim of any third person regarding infringement
* or the like. Any license provided herein, whether implied or
* otherwise, applies only to this software file. Patent licenses, if
* any, provided herein do not apply to combinations of this program with
* other software, or any other product whatsoever.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write the Free Software Foundation, Inc., 59
* Temple Place - Suite 330, Boston MA 02111-1307, USA.
*
* Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
* Mountain View, CA 94043, or:
*
* http://www.sgi.com
*
* For further information regarding this notice, see:
*
* http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
*/
#ifndef __XFS_SUPPORT_MRLOCK_H__
#define __XFS_SUPPORT_MRLOCK_H__
#include <linux/version.h>
#include <linux/time.h>
#include <linux/wait.h>
#include <asm/atomic.h>
#include <asm/semaphore.h>
/*
* Implement mrlocks on Linux that work for XFS.
*
* These are sleep locks and not spinlocks. If one wants read/write spinlocks,
* use read_lock, write_lock, ... see spinlock.h.
*/
typedef struct mrlock_s {
int mr_count;
uint mr_reads_waiting;
uint mr_writes_waiting;
wait_queue_head_t mr_readerq;
wait_queue_head_t mr_writerq;
spinlock_t mr_lock;
} mrlock_t;
#define MR_ACCESS 1
#define MR_UPDATE 2
#define MRLOCK_BARRIER 0x1
#define MRLOCK_ALLOW_EQUAL_PRI 0x8
/*
* mraccessf/mrupdatef take flags to be passed in while sleeping;
* only PLTWAIT is currently supported.
*/
extern void mraccessf(mrlock_t *, int);
extern void mrupdatef(mrlock_t *, int);
extern void mrlock(mrlock_t *, int, int);
extern void mrunlock(mrlock_t *);
extern void mraccunlock(mrlock_t *);
extern int mrtryupdate(mrlock_t *);
extern int mrtryaccess(mrlock_t *);
extern int mrtrypromote(mrlock_t *);
extern void mrdemote(mrlock_t *);
extern int ismrlocked(mrlock_t *, int);
extern void mrlock_init(mrlock_t *, int type, char *name, long sequence);
extern void mrfree(mrlock_t *);
#define mrinit(mrp, name) mrlock_init(mrp, MRLOCK_BARRIER, name, -1)
#define mraccess(mrp) mraccessf(mrp, 0) /* grab for READ/ACCESS */
#define mrupdate(mrp) mrupdatef(mrp, 0) /* grab for WRITE/UPDATE */
#endif /* __XFS_SUPPORT_MRLOCK_H__ */
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