thr_umtx.h revision 216641 
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 216641 2010-12-22 05:01:52Z 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#define DEFAULT_URWLOCK {0,0,0,0,{0,0,0,0}}
37
38int __thr_umutex_lock(struct umutex *mtx, uint32_t id) __hidden;
39int __thr_umutex_lock_spin(struct umutex *mtx, uint32_t id) __hidden;
40int __thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
41	const struct timespec *timeout) __hidden;
42int __thr_umutex_unlock(struct umutex *mtx, uint32_t id) __hidden;
43int __thr_umutex_trylock(struct umutex *mtx) __hidden;
44int __thr_umutex_set_ceiling(struct umutex *mtx, uint32_t ceiling,
45	uint32_t *oldceiling) __hidden;
46
47void _thr_umutex_init(struct umutex *mtx) __hidden;
48void _thr_urwlock_init(struct urwlock *rwl) __hidden;
49
50int _thr_umtx_wait(volatile long *mtx, long exp,
51	const struct timespec *timeout) __hidden;
52int _thr_umtx_wait_uint(volatile u_int *mtx, u_int exp,
53	const struct timespec *timeout, int shared) __hidden;
54int _thr_umtx_timedwait_uint(volatile u_int *mtx, u_int exp, int clockid,
55	const struct timespec *timeout, int shared) __hidden;
56int _thr_umtx_wake(volatile void *mtx, int count, int shared) __hidden;
57int _thr_ucond_wait(struct ucond *cv, struct umutex *m,
58        const struct timespec *timeout, int check_unpaking) __hidden;
59void _thr_ucond_init(struct ucond *cv) __hidden;
60int _thr_ucond_signal(struct ucond *cv) __hidden;
61int _thr_ucond_broadcast(struct ucond *cv) __hidden;
62
63int __thr_rwlock_rdlock(struct urwlock *rwlock, int flags, struct timespec *tsp) __hidden;
64int __thr_rwlock_wrlock(struct urwlock *rwlock, struct timespec *tsp) __hidden;
65int __thr_rwlock_unlock(struct urwlock *rwlock) __hidden;
66
67/* Internal used only */
68void _thr_rwl_rdlock(struct urwlock *rwlock) __hidden;
69void _thr_rwl_wrlock(struct urwlock *rwlock) __hidden;
70void _thr_rwl_unlock(struct urwlock *rwlock) __hidden;
71
72static inline int
73_thr_umutex_trylock(struct umutex *mtx, uint32_t id)
74{
75    if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id))
76	return (0);
77    if ((mtx->m_flags & UMUTEX_PRIO_PROTECT) == 0)
78    	return (EBUSY);
79    return (__thr_umutex_trylock(mtx));
80}
81
82static inline int
83_thr_umutex_trylock2(struct umutex *mtx, uint32_t id)
84{
85    if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_UNOWNED, id) != 0)
86	return (0);
87    if ((uint32_t)mtx->m_owner == UMUTEX_CONTESTED &&
88        __predict_true((mtx->m_flags & (UMUTEX_PRIO_PROTECT | UMUTEX_PRIO_INHERIT)) == 0))
89    	if (atomic_cmpset_acq_32(&mtx->m_owner, UMUTEX_CONTESTED, id | UMUTEX_CONTESTED))
90		return (0);
91    return (EBUSY);
92}
93
94static inline int
95_thr_umutex_lock(struct umutex *mtx, uint32_t id)
96{
97    if (_thr_umutex_trylock2(mtx, id) == 0)
98	return (0);
99    return (__thr_umutex_lock(mtx, id));
100}
101
102static inline int
103_thr_umutex_lock_spin(struct umutex *mtx, uint32_t id)
104{
105    if (_thr_umutex_trylock2(mtx, id) == 0)
106	return (0);
107    return (__thr_umutex_lock_spin(mtx, id));
108}
109
110static inline int
111_thr_umutex_timedlock(struct umutex *mtx, uint32_t id,
112	const struct timespec *timeout)
113{
114    if (_thr_umutex_trylock2(mtx, id) == 0)
115	return (0);
116    return (__thr_umutex_timedlock(mtx, id, timeout));
117}
118
119static inline int
120_thr_umutex_unlock(struct umutex *mtx, uint32_t id)
121{
122    if (atomic_cmpset_rel_32(&mtx->m_owner, id, UMUTEX_UNOWNED))
123	return (0);
124    return (__thr_umutex_unlock(mtx, id));
125}
126
127static inline int
128_thr_rwlock_tryrdlock(struct urwlock *rwlock, int flags)
129{
130	int32_t state;
131	int32_t wrflags;
132
133	if (flags & URWLOCK_PREFER_READER || rwlock->rw_flags & URWLOCK_PREFER_READER)
134		wrflags = URWLOCK_WRITE_OWNER;
135	else
136		wrflags = URWLOCK_WRITE_OWNER | URWLOCK_WRITE_WAITERS;
137	state = rwlock->rw_state;
138	while (!(state & wrflags)) {
139		if (__predict_false(URWLOCK_READER_COUNT(state) == URWLOCK_MAX_READERS))
140			return (EAGAIN);
141		if (atomic_cmpset_acq_32(&rwlock->rw_state, state, state + 1))
142			return (0);
143		state = rwlock->rw_state;
144	}
145
146	return (EBUSY);
147}
148
149static inline int
150_thr_rwlock_trywrlock(struct urwlock *rwlock)
151{
152	int32_t state;
153
154	state = rwlock->rw_state;
155	while (!(state & URWLOCK_WRITE_OWNER) && URWLOCK_READER_COUNT(state) == 0) {
156		if (atomic_cmpset_acq_32(&rwlock->rw_state, state, state | URWLOCK_WRITE_OWNER))
157			return (0);
158		state = rwlock->rw_state;
159	}
160
161	return (EBUSY);
162}
163
164static inline int
165_thr_rwlock_rdlock(struct urwlock *rwlock, int flags, struct timespec *tsp)
166{
167	if (_thr_rwlock_tryrdlock(rwlock, flags) == 0)
168		return (0);
169	return (__thr_rwlock_rdlock(rwlock, flags, tsp));
170}
171
172static inline int
173_thr_rwlock_wrlock(struct urwlock *rwlock, struct timespec *tsp)
174{
175	if (_thr_rwlock_trywrlock(rwlock) == 0)
176		return (0);
177	return (__thr_rwlock_wrlock(rwlock, tsp));
178}
179
180static inline int
181_thr_rwlock_unlock(struct urwlock *rwlock)
182{
183	int32_t state;
184
185	state = rwlock->rw_state;
186	if (state & URWLOCK_WRITE_OWNER) {
187		if (atomic_cmpset_rel_32(&rwlock->rw_state, URWLOCK_WRITE_OWNER, 0))
188			return (0);
189	} else {
190		for (;;) {
191			if (__predict_false(URWLOCK_READER_COUNT(state) == 0))
192				return (EPERM);
193			if (!((state & (URWLOCK_WRITE_WAITERS |
194			    URWLOCK_READ_WAITERS)) &&
195			    URWLOCK_READER_COUNT(state) == 1)) {
196				if (atomic_cmpset_rel_32(&rwlock->rw_state,
197				    state, state-1))
198					return (0);
199				state = rwlock->rw_state;
200			} else {
201				break;
202			}
203		}
204    	}
205    	return (__thr_rwlock_unlock(rwlock));
206}
207#endif
208