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authorLiu Xiang <liuxiang_1999@126.com>2019-11-30 17:49:53 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-12-01 06:29:18 -0800
commitd2dfbe47fa0e9753f560b75cfcd4654e40ab903b (patch)
treece7c80ddaeb4d04e91f2b1ec430029b2a9efbe81 /mm/gup.c
parentb96cc65515bb16f90a361c01da088ce09ad3cf92 (diff)
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 <liuxiang_1999@126.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c32
1 files 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.
*