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Sourcecode: fio version File versions

mutex.c

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <time.h>
#include <pthread.h>
#include <sys/mman.h>

#include "log.h"
#include "mutex.h"
#include "arch/arch.h"
#include "os/os.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, mflag;

      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;

      /*
       * Not all platforms support process shared mutexes (FreeBSD)
       */
#ifdef FIO_HAVE_PSHARED_MUTEX
      mflag = PTHREAD_PROCESS_SHARED;
#else
      mflag = PTHREAD_PROCESS_PRIVATE;
#endif

      ret = pthread_mutexattr_init(&attr);
      if (ret) {
            log_err("pthread_mutexattr_init: %s\n", strerror(ret));
            goto err;
      }
      ret = pthread_mutexattr_setpshared(&attr, mflag);
      if (ret) {
            log_err("pthread_mutexattr_setpshared: %s\n", strerror(ret));
            goto err;
      }

      pthread_condattr_init(&cond);
      pthread_condattr_setpshared(&cond, mflag);
      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;
}

int fio_mutex_down_timeout(struct fio_mutex *mutex, unsigned int seconds)
{
      struct timespec t;
      int ret = 0;

      clock_gettime(CLOCK_REALTIME, &t);
      t.tv_sec += seconds;

      pthread_mutex_lock(&mutex->lock);

      while (!mutex->value && !ret) {
            mutex->waiters++;
            ret = pthread_cond_timedwait(&mutex->cond, &mutex->lock, &t);
            mutex->waiters--;
      }

      if (!ret) {
            mutex->value--;
            pthread_mutex_unlock(&mutex->lock);
      }

      return ret;
}

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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