vla_group_size
vlabuf = kzalloc(vla_group_size(data_chunk), GFP_KERNEL);
char *vlabuf = kzalloc(vla_group_size(data_chunk), GFP_KERNEL);
char *vlabuf = kmalloc(vla_group_size(d), GFP_KERNEL);
vlabuf = kzalloc(vla_group_size(d), GFP_KERNEL);