GNTCOPY_dest_gref
op->flags = GNTCOPY_dest_gref;
if (!(seg->flags & (GNTCOPY_source_gref | GNTCOPY_dest_gref)))
if (seg->flags & GNTCOPY_dest_gref) {
if (seg->flags & GNTCOPY_dest_gref) {
op->flags |= GNTCOPY_dest_gref;