static inline int ds2781_battery_io(struct ds2781_device_info *dev_info,
        char *buf, int addr, size_t count, int io)
  {
 -      if (dev_info->mutex_holder == current)
 -              return w1_ds2781_io_nolock(dev_info->w1_dev, buf, addr,
 -                              count, io);
 -      else
 -              return w1_ds2781_io(dev_info->w1_dev, buf, addr, count, io);
 +      return w1_ds2781_io(dev_info->w1_dev, buf, addr, count, io);
  }
  
- int w1_ds2781_read(struct ds2781_device_info *dev_info, char *buf,
+ static int w1_ds2781_read(struct ds2781_device_info *dev_info, char *buf,
                int addr, size_t count)
  {
        return ds2781_battery_io(dev_info, buf, addr, count, 0);