On 10/24/19 8:04 AM, Liu Xiang wrote: > Fix comment of __get_user_pages() and make it more clear. > > Suggested-by: John Hubbard <jhubbard@xxxxxxxxxx> > Signed-off-by: Liu Xiang <liuxiang_1999@xxxxxxx> > --- > > Changes in v2: > as suggested by John, rewrite the comment about return value. > > mm/gup.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > Reviewed-by: John Hubbard <jhubbard@xxxxxxxxxx> thanks, -- John Hubbard NVIDIA > diff --git a/mm/gup.c b/mm/gup.c > index 8f236a3..bc6a254 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -734,11 +734,17 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) > * Or NULL if the caller does not require them. > * @nonblocking: whether waiting for disk IO or mmap_sem contention > * > - * Returns number of pages pinned. This may be fewer than the number > - * requested. If nr_pages is 0 or negative, returns 0. If no pages > - * were pinned, returns -errno. Each page returned must be released > - * with a put_page() call when it is finished with. vmas will only > - * remain valid while mmap_sem is held. > + * Returns either number of pages pinned (which may be less than the > + * number requested), or an error. Details about the return value: > + * > + * -- If nr_pages is 0, returns 0. > + * -- If nr_pages is >0, but no pages were pinned, returns -errno. > + * -- If nr_pages is >0, and some pages were pinned, returns the number of > + * pages pinned. Again, this may be less than nr_pages. > + * > + * The caller is responsible for releasing returned @pages, via put_page(). > + * > + * @vmas are valid only as long as mmap_sem is held. > * > * Must be called with mmap_sem held. It may be released. See below. > * >
