thr_umtx.h revision 179970 
1/*-
2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: head/lib/libthr/thread/thr_umtx.h 179970 2008-06-24 07:32:12Z davidxu $
27 */
28
29#ifndef _THR_FBSD_UMTX_H_
30#define _THR_FBSD_UMTX_H_
31
32#include <strings.h>
33#include <sys/umtx.h>
34
35#define DEFAULT_UMUTEX	{0,0, {0,0},{0,0,0,0}}
36
37int __thr_umutex_lock(struct umutex *mtx, uint32_t id) __hidden;
38int __thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
39	const struct timespec *timeout) __hidden;
40int __thr_umutex_unlock(struct umutex *mtx, uint32_t id) __hidden;
41int __thr_umutex_trylock(struct umutex *mtx) __hidden;
42int __thr_umutex_set_ceiling(struct umutex *mtx, uint32_t ceiling,
43	uint32_t *oldceiling) __hidden;
44
45void _thr_umutex_init(struct umutex *mtx) __hidden;
46int _thr_umtx_wait(volatile long *mtx, long exp,
47	const struct timespec *timeout) __hidden;
48int _thr_umtx_wait_uint(volatile u_int *mtx, u_int exp,
49	const struct timespec *timeout, int shared) __hidden;
50int _thr_umtx_wake(volatile void *mtx, int count, int shared) __hidden;
51int _thr_ucond_wait(struct ucond *cv, struct umutex *m,
52        const struct timespec *timeout, int check_unpaking) __hidden;
53void _thr_ucond_init(struct ucond *cv) __hidden;
54int _thr_ucond_signal(struct ucond *cv) __hidden;
55int _thr_ucond_broadcast(struct ucond *cv) __hidden;
56
57int __thr_rwlock_rdlock(struct urwlock *rwlock, int flags, struct timespec *tsp) __hidden;
58int __thr_rwlock_wrlock(struct urwlock *rwlock, struct timespec *tsp) __hidden;
59int __thr_rwlock_unlock(struct urwlock *rwlock) __hidden;
60
61static inline int
62_thr_umutex_trylock(struct umutex *mtx, uint32_t id)
63{
64    if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id))
65	return (0);
66    if ((mtx->m_flags & UMUTEX_PRIO_PROTECT) == 0)
67    	return (EBUSY);
68    return (__thr_umutex_trylock(mtx));
69}
70
71static inline int
72_thr_umutex_trylock2(struct umutex *mtx, uint32_t id)
73{
74    if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id) != 0)
75	return (0);
76    if ((uint32_t)mtx->m_owner == UMUTEX_CONTESTED &&
77        __predict_true((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0))
78    	if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_CONTESTED, id | UMUTEX_CONTESTED))
79		return (0);
80    return (EBUSY);
81}
82
83static inline int
84_thr_umutex_lock(struct umutex *mtx, uint32_t id)
85{
86    if (_thr_umutex_trylock2(mtx, id) == 0)
87	return (0);
88    return (__thr_umutex_lock(mtx, id));
89}
90
91static inline int
92_thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
93	const struct timespec *timeout)
94{
95    if (_thr_umutex_trylock2(mtx, id) == 0)
96	return (0);
97    return (__thr_umutex_timedlock(mtx, id, timeout));
98}
99
100static inline int
101_thr_umutex_unlock(struct umutex *mtx, uint32_t id)
102{
103    if (atomic_cmpset_rel_32(&mtx->m_owner, id, UMUTEX_UNOWNED))
104	return (0);
105    return (__thr_umutex_unlock(mtx, id));
106}
107
108static inline int
109_thr_rwlock_tryrdlock(struct urwlock *rwlock, int flags)
110{
111	int32_t state;
112	int32_t wrflags;
113
114	if (flags & URWLOCK_PREFER_READER || rwlock->rw_flags & URWLOCK_PREFER_READER)
115		wrflags = URWLOCK_WRITE_OWNER;
116	else
117		wrflags = URWLOCK_WRITE_OWNER | URWLOCK_WRITE_WAITERS;
118	state = rwlock->rw_state;
119	while (!(state & wrflags)) {
120		if (__predict_false(URWLOCK_READER_COUNT(state) == URWLOCK_MAX_READERS))
121			return (EAGAIN);
122		if (atomic_cmpset_acq_32(&rwlock->rw_state, state, state + 1))
123			return (0);
124		state = rwlock->rw_state;
125	}
126
127	return (EBUSY);
128}
129
130static inline int
131_thr_rwlock_trywrlock(struct urwlock *rwlock)
132{
133	int32_t state;
134
135	state = rwlock->rw_state;
136	while (!(state & URWLOCK_WRITE_OWNER) && URWLOCK_READER_COUNT(state) == 0) {
137		if (atomic_cmpset_acq_32(&rwlock->rw_state, state, state | URWLOCK_WRITE_OWNER))
138			return (0);
139		state = rwlock->rw_state;
140	}
141
142	return (EBUSY);
143}
144
145static inline int
146_thr_rwlock_rdlock(struct urwlock *rwlock, int flags, struct timespec *tsp)
147{
148	if (_thr_rwlock_tryrdlock(rwlock, flags) == 0)
149		return (0);
150	return (__thr_rwlock_rdlock(rwlock, flags, tsp));
151}
152
153static inline int
154_thr_rwlock_wrlock(struct urwlock *rwlock, struct timespec *tsp)
155{
156	if (_thr_rwlock_trywrlock(rwlock) == 0)
157		return (0);
158	return (__thr_rwlock_wrlock(rwlock, tsp));
159}
160
161static inline int
162_thr_rwlock_unlock(struct urwlock *rwlock)
163{
164	int32_t state;
165
166	state = rwlock->rw_state;
167	if (state & URWLOCK_WRITE_OWNER) {
168		if (atomic_cmpset_rel_32(&rwlock->rw_state, URWLOCK_WRITE_OWNER, 0))
169			return (0);
170	} else {
171		for (;;) {
172			if (__predict_false(URWLOCK_READER_COUNT(state) == 0))
173				return (EPERM);
174			if (!((state & URWLOCK_WRITE_WAITERS) && URWLOCK_READER_COUNT(state) == 1)) {
175				if (atomic_cmpset_rel_32(&rwlock->rw_state, state, state-1))
176					return (0);
177				state = rwlock->rw_state;
178			} else {
179				break;
180			}
181		}
182    	}
183    	return (__thr_rwlock_unlock(rwlock));
184}
185#endif
186