On Fri, Sep 11, 2020 at 12:04 PM Vasily Gorbik <gor@xxxxxxxxxxxxx> wrote: > > Currently to make sure that every page table entry is read just once > gup_fast walks perform READ_ONCE and pass pXd value down to the next > gup_pXd_range function by value e.g.: [ ... ] Ack, this looks sane to me. I was going to ask how horrible it would be to convert all the other users, but a quick grep convinced me that yeah, it's only GUP that is this special, and we don't want to make this interface be the real one for everything else too.. Linus