1 /*-
2 * Copyright (c) 2003 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 * $FreeBSD$
27 */
28
29 #include "namespace.h"
30 #include <errno.h>
31 #include <stdlib.h>
32 #include <pthread.h>
33 #include "un-namespace.h"
34
35 #include "thr_private.h"
36
37 #define SPIN_COUNT 100000
38
39 __weak_reference(_pthread_spin_init, pthread_spin_init);
40 __weak_reference(_pthread_spin_destroy, pthread_spin_destroy);
41 __weak_reference(_pthread_spin_trylock, pthread_spin_trylock);
42 __weak_reference(_pthread_spin_lock, pthread_spin_lock);
43 __weak_reference(_pthread_spin_unlock, pthread_spin_unlock);
44
45 int
_pthread_spin_init(pthread_spinlock_t * lock,int pshared)46 _pthread_spin_init(pthread_spinlock_t *lock, int pshared)
47 {
48 struct pthread_spinlock *lck;
49 int ret;
50
51 if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE)
52 ret = EINVAL;
53 else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL)
54 ret = ENOMEM;
55 else {
56 _thr_umutex_init(&lck->s_lock);
57 *lock = lck;
58 ret = 0;
59 }
60
61 return (ret);
62 }
63
64 int
_pthread_spin_destroy(pthread_spinlock_t * lock)65 _pthread_spin_destroy(pthread_spinlock_t *lock)
66 {
67 int ret;
68
69 if (lock == NULL || *lock == NULL)
70 ret = EINVAL;
71 else {
72 free(*lock);
73 *lock = NULL;
74 ret = 0;
75 }
76
77 return (ret);
78 }
79
80 int
_pthread_spin_trylock(pthread_spinlock_t * lock)81 _pthread_spin_trylock(pthread_spinlock_t *lock)
82 {
83 struct pthread *curthread = _get_curthread();
84 struct pthread_spinlock *lck;
85 int ret;
86
87 if (lock == NULL || (lck = *lock) == NULL)
88 ret = EINVAL;
89 else
90 ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock);
91 return (ret);
92 }
93
94 int
_pthread_spin_lock(pthread_spinlock_t * lock)95 _pthread_spin_lock(pthread_spinlock_t *lock)
96 {
97 struct pthread *curthread = _get_curthread();
98 struct pthread_spinlock *lck;
99 int ret, count;
100
101 if (lock == NULL || (lck = *lock) == NULL)
102 ret = EINVAL;
103 else {
104 count = SPIN_COUNT;
105 while ((ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock)) != 0) {
106 while (lck->s_lock.m_owner) {
107 if (!_thr_is_smp) {
108 _pthread_yield();
109 } else {
110 CPU_SPINWAIT;
111
112 if (--count <= 0) {
113 count = SPIN_COUNT;
114 _pthread_yield();
115 }
116 }
117 }
118 }
119 ret = 0;
120 }
121
122 return (ret);
123 }
124
125 int
_pthread_spin_unlock(pthread_spinlock_t * lock)126 _pthread_spin_unlock(pthread_spinlock_t *lock)
127 {
128 struct pthread *curthread = _get_curthread();
129 struct pthread_spinlock *lck;
130 int ret;
131
132 if (lock == NULL || (lck = *lock) == NULL)
133 ret = EINVAL;
134 else {
135 ret = THR_UMUTEX_UNLOCK(curthread, &lck->s_lock);
136 }
137 return (ret);
138 }
139