1/*-
 2 * SPDX-License-Identifier: BSD-2-Clause
 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
29#ifndef	_SYS_CONDVAR_H_
30#define	_SYS_CONDVAR_H_
31
32/*
33 * Condition variable.  The waiters count is protected by the mutex that
34 * protects the condition; that is, the mutex that is passed to cv_wait*()
35 * and is held across calls to cv_signal() and cv_broadcast().  It is an
36 * optimization to avoid looking up the sleep queue if there are no waiters.
37 */
38struct cv {
39	const char	*cv_description;
40	int		cv_waiters;
41};
42
43#ifdef _KERNEL
44#include <sys/types.h>
45
46struct lock_object;
47
48void	cv_init(struct cv *cvp, const char *desc);
49void	cv_destroy(struct cv *cvp);
50
51void	_cv_wait(struct cv *cvp, struct lock_object *lock);
52void	_cv_wait_unlock(struct cv *cvp, struct lock_object *lock);
53int	_cv_wait_sig(struct cv *cvp, struct lock_object *lock);
54int	_cv_timedwait_sbt(struct cv *cvp, struct lock_object *lock,
55	    sbintime_t sbt, sbintime_t pr, int flags);
56int	_cv_timedwait_sig_sbt(struct cv *cvp, struct lock_object *lock,
57	    sbintime_t sbt, sbintime_t pr, int flags);
58
59void	cv_signal(struct cv *cvp);
60void	cv_broadcastpri(struct cv *cvp, int pri);
61
62#define	cv_wait(cvp, lock)						\
63	_cv_wait((cvp), &(lock)->lock_object)
64#define	cv_wait_unlock(cvp, lock)					\
65	_cv_wait_unlock((cvp), &(lock)->lock_object)
66#define	cv_wait_sig(cvp, lock)						\
67	_cv_wait_sig((cvp), &(lock)->lock_object)
68#define	cv_timedwait(cvp, lock, timo)					\
69	_cv_timedwait_sbt((cvp), &(lock)->lock_object,			\
70	    tick_sbt * (timo), 0, C_HARDCLOCK)
71#define	cv_timedwait_sbt(cvp, lock, sbt, pr, flags)			\
72	_cv_timedwait_sbt((cvp), &(lock)->lock_object, (sbt), (pr), (flags))
73#define	cv_timedwait_sig(cvp, lock, timo)				\
74	_cv_timedwait_sig_sbt((cvp), &(lock)->lock_object,		\
75	    tick_sbt * (timo), 0, C_HARDCLOCK)
76#define	cv_timedwait_sig_sbt(cvp, lock, sbt, pr, flags)			\
77	_cv_timedwait_sig_sbt((cvp), &(lock)->lock_object, (sbt), (pr), (flags))
78
79#define cv_broadcast(cvp)	cv_broadcastpri(cvp, 0)
80
81#define	cv_wmesg(cvp)		((cvp)->cv_description)
82
83#endif	/* _KERNEL */
84#endif	/* _SYS_CONDVAR_H_ */