+ *
+ * XXX: This is racy against mmap, and there's nothing we can do about
+ * it. dax_do_io() should really do this invalidation internally as
+ * it will know if we've allocated over a holei for this specific IO and
+ * if so it needs to update the mapping tree and invalidate existing
+ * PTEs over the newly allocated range. Remove this invalidation when
+ * dax_do_io() is fixed up.