nbd: Update for libnbd 0.9.8
[fio.git] / fio_sem.c
CommitLineData
3d2d14bc 1#include <stdio.h>
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2#include <string.h>
3#include <sys/mman.h>
4#include <assert.h>
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5#ifdef CONFIG_VALGRIND_DEV
6#include <valgrind/valgrind.h>
7#else
8#define RUNNING_ON_VALGRIND 0
9#endif
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11#include "fio_sem.h"
12#include "pshared.h"
13#include "os/os.h"
14#include "fio_time.h"
15#include "gettime.h"
16
17void __fio_sem_remove(struct fio_sem *sem)
18{
19 assert(sem->magic == FIO_SEM_MAGIC);
0ffccc21 20 pthread_mutex_destroy(&sem->lock);
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21 pthread_cond_destroy(&sem->cond);
22
23 /*
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24 * When not running on Valgrind, ensure any subsequent attempt to grab
25 * this semaphore will fail with an assert, instead of just silently
26 * hanging. When running on Valgrind, let Valgrind detect
27 * use-after-free.
28 */
29 if (!RUNNING_ON_VALGRIND)
30 memset(sem, 0, sizeof(*sem));
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31}
32
33void fio_sem_remove(struct fio_sem *sem)
34{
35 __fio_sem_remove(sem);
36 munmap((void *) sem, sizeof(*sem));
37}
38
39int __fio_sem_init(struct fio_sem *sem, int value)
40{
41 int ret;
42
43 sem->value = value;
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44 /* Initialize .waiters explicitly for Valgrind. */
45 sem->waiters = 0;
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46 sem->magic = FIO_SEM_MAGIC;
47
48 ret = mutex_cond_init_pshared(&sem->lock, &sem->cond);
49 if (ret)
50 return ret;
51
52 return 0;
53}
54
55struct fio_sem *fio_sem_init(int value)
56{
57 struct fio_sem *sem = NULL;
58
59 sem = (void *) mmap(NULL, sizeof(struct fio_sem),
60 PROT_READ | PROT_WRITE,
61 OS_MAP_ANON | MAP_SHARED, -1, 0);
62 if (sem == MAP_FAILED) {
63 perror("mmap semaphore");
64 return NULL;
65 }
66
67 if (!__fio_sem_init(sem, value))
68 return sem;
69
70 fio_sem_remove(sem);
71 return NULL;
72}
73
74static bool sem_timed_out(struct timespec *t, unsigned int msecs)
75{
76 struct timeval tv;
77 struct timespec now;
78
79 gettimeofday(&tv, NULL);
80 now.tv_sec = tv.tv_sec;
81 now.tv_nsec = tv.tv_usec * 1000;
82
83 return mtime_since(t, &now) >= msecs;
84}
85
86int fio_sem_down_timeout(struct fio_sem *sem, unsigned int msecs)
87{
88 struct timeval tv_s;
89 struct timespec base;
90 struct timespec t;
91 int ret = 0;
92
93 assert(sem->magic == FIO_SEM_MAGIC);
94
95 gettimeofday(&tv_s, NULL);
96 base.tv_sec = t.tv_sec = tv_s.tv_sec;
97 base.tv_nsec = t.tv_nsec = tv_s.tv_usec * 1000;
98
99 t.tv_sec += msecs / 1000;
100 t.tv_nsec += ((msecs * 1000000ULL) % 1000000000);
101 if (t.tv_nsec >= 1000000000) {
102 t.tv_nsec -= 1000000000;
103 t.tv_sec++;
104 }
105
106 pthread_mutex_lock(&sem->lock);
107
108 sem->waiters++;
109 while (!sem->value && !ret) {
110 /*
111 * Some platforms (FreeBSD 9?) seems to return timed out
112 * way too early, double check.
113 */
114 ret = pthread_cond_timedwait(&sem->cond, &sem->lock, &t);
115 if (ret == ETIMEDOUT && !sem_timed_out(&base, msecs))
116 ret = 0;
117 }
118 sem->waiters--;
119
120 if (!ret) {
121 sem->value--;
122 pthread_mutex_unlock(&sem->lock);
123 return 0;
124 }
125
126 pthread_mutex_unlock(&sem->lock);
127 return ret;
128}
129
130bool fio_sem_down_trylock(struct fio_sem *sem)
131{
132 bool ret = true;
133
134 assert(sem->magic == FIO_SEM_MAGIC);
135
136 pthread_mutex_lock(&sem->lock);
137 if (sem->value) {
138 sem->value--;
139 ret = false;
140 }
141 pthread_mutex_unlock(&sem->lock);
142
143 return ret;
144}
145
146void fio_sem_down(struct fio_sem *sem)
147{
148 assert(sem->magic == FIO_SEM_MAGIC);
149
150 pthread_mutex_lock(&sem->lock);
151
152 while (!sem->value) {
153 sem->waiters++;
154 pthread_cond_wait(&sem->cond, &sem->lock);
155 sem->waiters--;
156 }
157
158 sem->value--;
159 pthread_mutex_unlock(&sem->lock);
160}
161
162void fio_sem_up(struct fio_sem *sem)
163{
164 int do_wake = 0;
165
166 assert(sem->magic == FIO_SEM_MAGIC);
167
168 pthread_mutex_lock(&sem->lock);
169 read_barrier();
170 if (!sem->value && sem->waiters)
171 do_wake = 1;
172 sem->value++;
173
174 if (do_wake)
175 pthread_cond_signal(&sem->cond);
176
177 pthread_mutex_unlock(&sem->lock);
178}