1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21/*
22 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 */
25
26/*
27 * Copyright (c) 2013, Joyent, Inc.  All rights reserved.
28 */
29
30#ifndef _SYS_RWLOCK_H
31#define	_SYS_RWLOCK_H
32
33/*
34 * Public interface to readers/writer locks.  See rwlock(9F) for details.
35 */
36
37#include <sys/types.h>
38
39#ifdef	__cplusplus
40extern "C" {
41#endif
42
43#ifndef _ASM
44
45typedef enum {
46	RW_DRIVER = 2,		/* driver (DDI) rwlock */
47	RW_DEFAULT = 4		/* kernel default rwlock */
48} krw_type_t;
49
50typedef enum {
51	RW_WRITER,
52	RW_READER,
53	RW_READER_STARVEWRITER
54} krw_t;
55
56typedef struct _krwlock {
57	void	*_opaque[1];
58} krwlock_t;
59
60#if defined(_KERNEL)
61
62#define	RW_READ_HELD(x)		(rw_read_held((x)))
63#define	RW_WRITE_HELD(x)	(rw_write_held((x)))
64#define	RW_LOCK_HELD(x)		(rw_lock_held((x)))
65#define	RW_ISWRITER(x)		(rw_iswriter(x))
66
67extern	void	rw_init(krwlock_t *, char *, krw_type_t, void *);
68extern	void	rw_destroy(krwlock_t *);
69extern	void	rw_enter(krwlock_t *, krw_t);
70extern	int	rw_tryenter(krwlock_t *, krw_t);
71extern	void	rw_exit(krwlock_t *);
72extern	void	rw_downgrade(krwlock_t *);
73extern	int	rw_tryupgrade(krwlock_t *);
74extern	int	rw_read_held(krwlock_t *);
75extern	int	rw_write_held(krwlock_t *);
76extern	int	rw_lock_held(krwlock_t *);
77extern	int	rw_read_locked(krwlock_t *);
78extern	int	rw_iswriter(krwlock_t *);
79extern	struct _kthread *rw_owner(krwlock_t *);
80extern	uint_t (*rw_lock_backoff)(uint_t);
81extern	void (*rw_lock_delay)(uint_t);
82
83#endif	/* defined(_KERNEL) */
84
85#endif	/* _ASM */
86
87#ifdef	__cplusplus
88}
89#endif
90
91#endif	/* _SYS_RWLOCK_H */
92