mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE);
mapping->assoc_mapping = NULL;
mapping->backing_dev_info = &default_backing_dev_info;
mapping_set_gfp_mask(mapping, GFP_HIGHUSER_PAGECACHE);
mapping->assoc_mapping = NULL;
mapping->backing_dev_info = &default_backing_dev_info;