1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2007 Stephan Uphoff <ups@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the author nor the names of any co-contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#ifndef _SYS__RMLOCK_H_
33#define	_SYS__RMLOCK_H_
34
35/*
36 * Mostly reader/occasional writer lock.
37 */
38
39LIST_HEAD(rmpriolist,rm_priotracker);
40
41struct rm_queue {
42	struct rm_queue	*volatile rmq_next;
43	struct rm_queue	*volatile rmq_prev;
44};
45
46struct rmlock {
47	struct lock_object lock_object;
48	volatile cpuset_t rm_writecpus;
49	LIST_HEAD(,rm_priotracker) rm_activeReaders;
50	union {
51		struct lock_object _rm_wlock_object;
52		struct mtx _rm_lock_mtx;
53		struct sx _rm_lock_sx;
54	} _rm_lock;
55};
56
57#define	rm_wlock_object	_rm_lock._rm_wlock_object
58#define	rm_lock_mtx	_rm_lock._rm_lock_mtx
59#define	rm_lock_sx	_rm_lock._rm_lock_sx
60
61struct rm_priotracker {
62	struct rm_queue rmp_cpuQueue; /* Must be first */
63	struct rmlock *rmp_rmlock;
64	struct thread *rmp_thread;
65	int rmp_flags;
66	LIST_ENTRY(rm_priotracker) rmp_qentry;
67};
68
69#include <sys/_mutex.h>
70
71struct rmslock_pcpu;
72
73struct rmslock {
74	struct mtx mtx;
75	struct thread *owner;
76	struct rmslock_pcpu *pcpu;
77	int	writers;
78	int	readers;
79	int	debug_readers;
80};
81
82#endif /* !_SYS__RMLOCK_H_ */
83