static ssize_t delete_store()

in bus.c [462:509]

• 36 lines of code
• 9 McCabe index (conditional complexity)

static ssize_t delete_store(struct device *dev, struct device_attribute *attr,
		const char *buf, size_t len)
{
	struct dax_region *dax_region = dev_get_drvdata(dev);
	struct dev_dax *dev_dax;
	struct device *victim;
	bool do_del = false;
	int rc;

	if (is_static(dax_region))
		return -EINVAL;

	victim = device_find_child_by_name(dax_region->dev, buf);
	if (!victim)
		return -ENXIO;

	device_lock(dev);
	device_lock(victim);
	dev_dax = to_dev_dax(victim);
	if (victim->driver || dev_dax_size(dev_dax))
		rc = -EBUSY;
	else {
		/*
		 * Invalidate the device so it does not become active
		 * again, but always preserve device-id-0 so that
		 * /sys/bus/dax/ is guaranteed to be populated while any
		 * dax_region is registered.
		 */
		if (dev_dax->id > 0) {
			do_del = __free_dev_dax_id(dev_dax) >= 0;
			rc = len;
			if (dax_region->seed == victim)
				dax_region->seed = NULL;
			if (dax_region->youngest == victim)
				dax_region->youngest = NULL;
		} else
			rc = -EBUSY;
	}
	device_unlock(victim);

	/* won the race to invalidate the device, clean it up */
	if (do_del)
		devm_release_action(dev, unregister_dev_dax, victim);
	device_unlock(dev);
	put_device(victim);

	return rc;
}