As per documentation, pin_user_pages_fast() & get_user_pages_fast() will return 0, if nr_pages <= 0. But this can be figure out only after going inside the internal_get_user_pages_fast(). This can be handled early. Adding a check for the same. Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx> --- mm/gup.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/gup.c b/mm/gup.c index 50681f0..a13aaa6 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -2817,6 +2817,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, */ if (WARN_ON_ONCE(gup_flags & FOLL_PIN)) return -EINVAL; + if (nr_pages <= 0) + return 0; /* * The caller may or may not have explicitly set FOLL_GET; either way is @@ -2854,6 +2856,8 @@ int pin_user_pages_fast(unsigned long start, int nr_pages, /* FOLL_GET and FOLL_PIN are mutually exclusive. */ if (WARN_ON_ONCE(gup_flags & FOLL_GET)) return -EINVAL; + if (nr_pages <= 0) + return 0; gup_flags |= FOLL_PIN; return internal_get_user_pages_fast(start, nr_pages, gup_flags, pages); -- 1.9.1
