static ssize_t w1_master_attribute_show_slave_count(struct device *dev, char *buf)
static ssize_t w1_master_attribute_show_slave_count(struct device *dev, struct device_attribute *attr, char *buf)
static ssize_t w1_master_attribute_show_slave_count(struct device *dev, char *buf){	struct w1_master *md = container_of(dev, struct w1_master, dev);	ssize_t count;		if (down_interruptible(&md->mutex))		return -EBUSY;	count = sprintf(buf, "%d\n", md->slave_count);		up(&md->mutex);	return count;}