spinlock.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5 #include <fcntl.h>
   6 #include <pthread.h>
   7 #include <sys/mman.h>
   8
   9 #include "arch/arch.h"
  10 #include "spinlock.h"
  11
  12 void fio_spinlock_remove(struct fio_spinlock *lock)
  13 {
  14         close(lock->lock_fd);
  15         munmap((void *) lock, sizeof(*lock));
  16 }
  17
  18 struct fio_spinlock *fio_spinlock_init(void)
  19 {
  20         char spinlock_name[] = "/tmp/.fio_spinlock.XXXXXX";
  21         struct fio_spinlock *lock = NULL;
  22         int fd;
  23
  24         fd = mkstemp(spinlock_name);
  25         if (fd < 0) {
  26                 perror("open spinlock");
  27                 return NULL;
  28         }
  29
  30         if (ftruncate(fd, sizeof(struct fio_spinlock)) < 0) {
  31                 perror("ftruncate spinlock");
  32                 goto err;
  33         }
  34
  35         lock = (void *) mmap(NULL, sizeof(struct fio_spinlock),
  36                                 PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
  37         if (lock == MAP_FAILED) {
  38                 perror("mmap spinlock");
  39                 close(fd);
  40                 lock = NULL;
  41                 goto err;
  42         }
  43
  44         unlink(spinlock_name);
  45         lock->lock_fd = fd;
  46         spin_lock_init(&lock->slock);
  47
  48         return lock;
  49 err:
  50         if (lock)
  51                 fio_spinlock_remove(lock);
  52
  53         unlink(spinlock_name);
  54         return NULL;
  55 }