static int table_clear(struct file *filp, struct dm_ioctl *param, size_t param_size)
{
	struct hash_cell *hc;
	struct mapped_device *md;
	struct dm_table *old_map = NULL;

	down_write(&_hash_lock);

	hc = __find_device_hash_cell(param);
	if (!hc) {
		DMDEBUG_LIMIT("device doesn't appear to be in the dev hash table.");
		up_write(&_hash_lock);
		return -ENXIO;
	}

	if (hc->new_map) {
		old_map = hc->new_map;
		hc->new_map = NULL;
	}

	param->flags &= ~DM_INACTIVE_PRESENT_FLAG;

	__dev_status(hc->md, param);
	md = hc->md;
	up_write(&_hash_lock);
	if (old_map) {
		dm_sync_table(md);
		dm_table_destroy(old_map);
	}
	dm_put(md);

	return 0;
}
Unknown