11556Srgrimes/*-
250471Speter * Copyright (c) 2007 Stephan Uphoff <ups@FreeBSD.org>
31556Srgrimes * All rights reserved.
4235655Smarcel *
5235655Smarcel * Redistribution and use in source and binary forms, with or without
61556Srgrimes * modification, are permitted provided that the following conditions
7105832Srwatson * are met:
8129719Spjd * 1. Redistributions of source code must retain the above copyright
9129719Spjd *    notice, this list of conditions and the following disclaimer.
101556Srgrimes * 2. Redistributions in binary form must reproduce the above copyright
11235655Smarcel *    notice, this list of conditions and the following disclaimer in the
12235655Smarcel *    documentation and/or other materials provided with the distribution.
1361268Sjoe * 3. Neither the name of the author nor the names of any co-contributors
1488671Sbde *    may be used to endorse or promote products derived from this software
1588671Sbde *    without specific prior written permission.
1661269Sjoe *
1761268Sjoe * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18289965Sngie * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19289965Sngie * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20289965Sngie * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21289965Sngie * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
221556Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD$
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#endif /* !_SYS__RMLOCK_H_ */
70