diff --git a/mm/gup.c b/mm/gup.c
index 49c4eabca271..f3751bf28326 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1924,66 +1924,68 @@ static long __get_user_pages_remote(struct mm_struct *mm,
  *              Or NULL if the caller does not require them.
  *
  * This is the same as get_user_pages_remote(), just with a less-flexible
  * calling convention where we assume that the mm being operated on belongs to
  * the current task, and doesn't allow passing of a locked parameter.  We also
  * obviously don't pass FOLL_REMOTE in here.
  */
 long get_user_pages(unsigned long start, unsigned long nr_pages,
 		unsigned int gup_flags, struct page **pages,
 		struct vm_area_struct **vmas)
 {
 	if (!is_valid_gup_flags(gup_flags))
 		return -EINVAL;
 
 	return __gup_longterm_locked(current->mm, start, nr_pages,
 				     pages, vmas, gup_flags | FOLL_TOUCH);
 }
 EXPORT_SYMBOL(get_user_pages);
 
 /**
- * get_user_pages_locked() is suitable to replace the form:
+ * get_user_pages_locked() - variant of get_user_pages()
+ *
+ * @start:      starting user address
+ * @nr_pages:   number of pages from start to pin
+ * @gup_flags:  flags modifying lookup behaviour
+ * @pages:      array that receives pointers to the pages pinned.
+ *              Should be at least nr_pages long. Or NULL, if caller
+ *              only intends to ensure the pages are faulted in.
+ * @locked:     pointer to lock flag indicating whether lock is held and
+ *              subsequently whether VM_FAULT_RETRY functionality can be
+ *              utilised. Lock must initially be held.
+ *
+ * It is suitable to replace the form:
  *
  *      mmap_read_lock(mm);
  *      do_something()
  *      get_user_pages(mm, ..., pages, NULL);
  *      mmap_read_unlock(mm);
  *
  *  to:
  *
  *      int locked = 1;
  *      mmap_read_lock(mm);
  *      do_something()
  *      get_user_pages_locked(mm, ..., pages, &locked);
  *      if (locked)
  *          mmap_read_unlock(mm);
  *
- * @start:      starting user address
- * @nr_pages:   number of pages from start to pin
- * @gup_flags:  flags modifying lookup behaviour
- * @pages:      array that receives pointers to the pages pinned.
- *              Should be at least nr_pages long. Or NULL, if caller
- *              only intends to ensure the pages are faulted in.
- * @locked:     pointer to lock flag indicating whether lock is held and
- *              subsequently whether VM_FAULT_RETRY functionality can be
- *              utilised. Lock must initially be held.
- *
  * We can leverage the VM_FAULT_RETRY functionality in the page fault
  * paths better by using either get_user_pages_locked() or
  * get_user_pages_unlocked().
  *
  */
 long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
 			   unsigned int gup_flags, struct page **pages,
 			   int *locked)
 {
 	/*
 	 * FIXME: Current FOLL_LONGTERM behavior is incompatible with
 	 * FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
 	 * vmas.  As there are no users of this flag in this call we simply
 	 * disallow this option for now.
 	 */
 	if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
 		return -EINVAL;
 	/*
 	 * FOLL_PIN must only be set internally by the pin_user_pages*() APIs,
 	 * never directly by the caller, so enforce that:
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 63d8d8b72c10..7e4d1e4bdee9 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -478,66 +478,66 @@ static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
 static inline unsigned long *get_pageblock_bitmap(struct page *page,
 							unsigned long pfn)
 {
 #ifdef CONFIG_SPARSEMEM
 	return section_to_usemap(__pfn_to_section(pfn));
 #else
 	return page_zone(page)->pageblock_flags;
 #endif /* CONFIG_SPARSEMEM */
 }
 
 static inline int pfn_to_bitidx(struct page *page, unsigned long pfn)
 {
 #ifdef CONFIG_SPARSEMEM
 	pfn &= (PAGES_PER_SECTION-1);
 #else
 	pfn = pfn - round_down(page_zone(page)->zone_start_pfn, pageblock_nr_pages);
 #endif /* CONFIG_SPARSEMEM */
 	return (pfn >> pageblock_order) * NR_PAGEBLOCK_BITS;
 }
 
-/**
- * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
- * @page: The page within the block of interest
- * @pfn: The target page frame number
- * @mask: mask of bits that the caller is interested in
- *
- * Return: pageblock_bits flags
- */
 static __always_inline
 unsigned long __get_pfnblock_flags_mask(struct page *page,
 					unsigned long pfn,
 					unsigned long mask)
 {
 	unsigned long *bitmap;
 	unsigned long bitidx, word_bitidx;
 	unsigned long word;
 
 	bitmap = get_pageblock_bitmap(page, pfn);
 	bitidx = pfn_to_bitidx(page, pfn);
 	word_bitidx = bitidx / BITS_PER_LONG;
 	bitidx &= (BITS_PER_LONG-1);
 
 	word = bitmap[word_bitidx];
 	return (word >> bitidx) & mask;
 }
 
+/**
+ * get_pfnblock_flags_mask - Return the requested group of flags for the pageblock_nr_pages block of pages
+ * @page: The page within the block of interest
+ * @pfn: The target page frame number
+ * @mask: mask of bits that the caller is interested in
+ *
+ * Return: pageblock_bits flags
+ */
 unsigned long get_pfnblock_flags_mask(struct page *page, unsigned long pfn,
 					unsigned long mask)
 {
 	return __get_pfnblock_flags_mask(page, pfn, mask);
 }
 
 static __always_inline int get_pfnblock_migratetype(struct page *page, unsigned long pfn)
 {
 	return __get_pfnblock_flags_mask(page, pfn, MIGRATETYPE_MASK);
 }
 
 /**
  * set_pfnblock_flags_mask - Set the requested group of flags for a pageblock_nr_pages block of pages
  * @page: The page within the block of interest
  * @flags: The flags to set
  * @pfn: The target page frame number
  * @mask: mask of bits that the caller is interested in
  */
 void set_pfnblock_flags_mask(struct page *page, unsigned long flags,
 					unsigned long pfn,
diff --git a/mm/truncate.c b/mm/truncate.c
index 960edf5803ca..604eaabc6d06 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -620,43 +620,49 @@ static unsigned long __invalidate_mapping_pages(struct address_space *mapping,
  * @start: the offset 'from' which to invalidate
  * @end: the offset 'to' which to invalidate (inclusive)
  *
  * This function only removes the unlocked pages, if you want to
  * remove all the pages of one inode, you must call truncate_inode_pages.
  *
  * invalidate_mapping_pages() will not block on IO activity. It will not
  * invalidate pages which are dirty, locked, under writeback or mapped into
  * pagetables.
  *
  * Return: the number of the pages that were invalidated
  */
 unsigned long invalidate_mapping_pages(struct address_space *mapping,
 		pgoff_t start, pgoff_t end)
 {
 	return __invalidate_mapping_pages(mapping, start, end, NULL);
 }
 EXPORT_SYMBOL(invalidate_mapping_pages);
 
 /**
- * This helper is similar with the above one, except that it accounts for pages
- * that are likely on a pagevec and count them in @nr_pagevec, which will used by
+ * invalidate_mapping_pagevec - This helper is similar to
+ * invalidate_mapping_pages(), except that it accounts for pages that are
+ * likely on a pagevec and count them in @nr_pagevec, which will be used by
  * the caller.
+ *
+ * @mapping: the address_space which holds the pages to invalidate
+ * @start: the offset 'from' which to invalidate
+ * @end: the offset 'to' which to invalidate (inclusive)
+ *
  */
 void invalidate_mapping_pagevec(struct address_space *mapping,
 		pgoff_t start, pgoff_t end, unsigned long *nr_pagevec)
 {
 	__invalidate_mapping_pages(mapping, start, end, nr_pagevec);
 }
 
 /*
  * This is like invalidate_complete_page(), except it ignores the page's
  * refcount.  We do this because invalidate_inode_pages2() needs stronger
  * invalidation guarantees, and cannot afford to leave pages behind because
  * shrink_page_list() has a temp ref on them, or because they're transiently
  * sitting in the lru_cache_add() pagevecs.
  */
 static int
 invalidate_complete_page2(struct address_space *mapping, struct page *page)
 {
 	unsigned long flags;
 
 	if (page->mapping != mapping)
