1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2000 Jake Burkholder <jake@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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31#ifndef	_SYS_CONDVAR_H_
32#define	_SYS_CONDVAR_H_
33
34#ifndef	LOCORE
35#include <sys/queue.h>
36
37struct lock_object;
38struct thread;
39
40TAILQ_HEAD(cv_waitq, thread);
41
42/*
43 * Condition variable.  The waiters count is protected by the mutex that
44 * protects the condition; that is, the mutex that is passed to cv_wait*()
45 * and is held across calls to cv_signal() and cv_broadcast().  It is an
46 * optimization to avoid looking up the sleep queue if there are no waiters.
47 */
48struct cv {
49	const char	*cv_description;
50	int		cv_waiters;
51};
52
53#ifdef _KERNEL
54void	cv_init(struct cv *cvp, const char *desc);
55void	cv_destroy(struct cv *cvp);
56
57void	_cv_wait(struct cv *cvp, struct lock_object *lock);
58void	_cv_wait_unlock(struct cv *cvp, struct lock_object *lock);
59int	_cv_wait_sig(struct cv *cvp, struct lock_object *lock);
60int	_cv_timedwait_sbt(struct cv *cvp, struct lock_object *lock,
61	    sbintime_t sbt, sbintime_t pr, int flags);
62int	_cv_timedwait_sig_sbt(struct cv *cvp, struct lock_object *lock,
63	    sbintime_t sbt, sbintime_t pr, int flags);
64
65void	cv_signal(struct cv *cvp);
66void	cv_broadcastpri(struct cv *cvp, int pri);
67
68#define	cv_wait(cvp, lock)						\
69	_cv_wait((cvp), &(lock)->lock_object)
70#define	cv_wait_unlock(cvp, lock)					\
71	_cv_wait_unlock((cvp), &(lock)->lock_object)
72#define	cv_wait_sig(cvp, lock)						\
73	_cv_wait_sig((cvp), &(lock)->lock_object)
74#define	cv_timedwait(cvp, lock, timo)					\
75	_cv_timedwait_sbt((cvp), &(lock)->lock_object,			\
76	    tick_sbt * (timo), 0, C_HARDCLOCK)
77#define	cv_timedwait_sbt(cvp, lock, sbt, pr, flags)			\
78	_cv_timedwait_sbt((cvp), &(lock)->lock_object, (sbt), (pr), (flags))
79#define	cv_timedwait_sig(cvp, lock, timo)				\
80	_cv_timedwait_sig_sbt((cvp), &(lock)->lock_object,		\
81	    tick_sbt * (timo), 0, C_HARDCLOCK)
82#define	cv_timedwait_sig_sbt(cvp, lock, sbt, pr, flags)			\
83	_cv_timedwait_sig_sbt((cvp), &(lock)->lock_object, (sbt), (pr), (flags))
84
85#define cv_broadcast(cvp)	cv_broadcastpri(cvp, 0)
86
87#define	cv_wmesg(cvp)		((cvp)->cv_description)
88
89#endif	/* _KERNEL */
90#endif	/* !LOCORE */
91#endif	/* _SYS_CONDVAR_H_ */
92