From d2dfbe47fa0e9753f560b75cfcd4654e40ab903b Mon Sep 17 00:00:00 2001 From: Liu Xiang Date: Sat, 30 Nov 2019 17:49:53 -0800 Subject: [PATCH] mm/gup.c: fix comments of __get_user_pages() and get_user_pages_remote() Fix comments of __get_user_pages() and get_user_pages_remote(), make them more clear. Link: http://lkml.kernel.org/r/1572443533-3118-1-git-send-email-liuxiang_1999@126.com Signed-off-by: Liu Xiang Suggested-by: John Hubbard Reviewed-by: David Hildenbrand Reviewed-by: John Hubbard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/gup.c | 32 ++++++++++++++++++++++---------- 1 file changed, 22 insertions(+), 10 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index c2b3e117d706..7646bf993b25 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. * @@ -1107,11 +1113,17 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk, * subsequently whether VM_FAULT_RETRY functionality can be * utilised. Lock must initially be held. * - * 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 for read or write. *