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#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <pthread.h>
#include <sys/mman.h>
#include "log.h"
#include "mutex.h"
#include "arch/arch.h"
void fio_mutex_remove(struct fio_mutex *mutex)
{
close(mutex->mutex_fd);
munmap((void *) mutex, sizeof(*mutex));
}
struct fio_mutex *fio_mutex_init(int value)
{
char mutex_name[] = "/tmp/.fio_mutex.XXXXXX";
struct fio_mutex *mutex = NULL;
pthread_mutexattr_t attr;
pthread_condattr_t cond;
int fd, ret;
fd = mkstemp(mutex_name);
if (fd < 0) {
perror("open mutex");
return NULL;
}
if (ftruncate(fd, sizeof(struct fio_mutex)) < 0) {
perror("ftruncate mutex");
goto err;
}
mutex = (void *) mmap(NULL, sizeof(struct fio_mutex),
PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (mutex == MAP_FAILED) {
perror("mmap mutex");
close(fd);
mutex = NULL;
goto err;
}
unlink(mutex_name);
mutex->mutex_fd = fd;
mutex->value = value;
ret = pthread_mutexattr_init(&attr);
if (ret) {
log_err("pthread_mutexattr_init: %s\n", strerror(ret));
goto err;
}
ret = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
if (ret) {
log_err("pthread_mutexattr_setpshared: %s\n", strerror(ret));
goto err;
}
pthread_condattr_init(&cond);
pthread_condattr_setpshared(&cond, PTHREAD_PROCESS_SHARED);
pthread_cond_init(&mutex->cond, &cond);
ret = pthread_mutex_init(&mutex->lock, &attr);
if (ret) {
log_err("pthread_mutex_init: %s\n", strerror(ret));
goto err;
}
return mutex;
err:
if (mutex)
fio_mutex_remove(mutex);
unlink(mutex_name);
return NULL;
}
void fio_mutex_down(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
while (!mutex->value) {
mutex->waiters++;
pthread_cond_wait(&mutex->cond, &mutex->lock);
mutex->waiters--;
}
mutex->value--;
pthread_mutex_unlock(&mutex->lock);
}
void fio_mutex_up(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
read_barrier();
if (!mutex->value && mutex->waiters)
pthread_cond_signal(&mutex->cond);
mutex->value++;
pthread_mutex_unlock(&mutex->lock);
}
void fio_mutex_down_write(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
while (mutex->value != 0) {
mutex->waiters++;
pthread_cond_wait(&mutex->cond, &mutex->lock);
mutex->waiters--;
}
mutex->value--;
pthread_mutex_unlock(&mutex->lock);
}
void fio_mutex_down_read(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
while (mutex->value < 0) {
mutex->waiters++;
pthread_cond_wait(&mutex->cond, &mutex->lock);
mutex->waiters--;
}
mutex->value++;
pthread_mutex_unlock(&mutex->lock);
}
void fio_mutex_up_read(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
mutex->value--;
read_barrier();
if (mutex->value >= 0 && mutex->waiters)
pthread_cond_signal(&mutex->cond);
pthread_mutex_unlock(&mutex->lock);
}
void fio_mutex_up_write(struct fio_mutex *mutex)
{
pthread_mutex_lock(&mutex->lock);
mutex->value++;
read_barrier();
if (mutex->value >= 0 && mutex->waiters)
pthread_cond_signal(&mutex->cond);
pthread_mutex_unlock(&mutex->lock);
}
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