On Tue, Oct 27, 2020 at 10:33:01AM +0100, Jan Kara wrote: > Actually there are callers that care about partial success. See e.g. > iov_iter_get_pages() usage in fs/direct_io.c:dio_refill_pages() or > bio_iov_iter_get_pages(). These places handle partial success just fine and > not allowing partial success from GUP could regress things...
But most users do indeed not care. Maybe an explicit FOLL_PARTIAL to opt into partial handling could clean up a lot of the mess. Maybe just for pin_user_pages for now.
