docs/core-api/mm: fix return value descriptions in mm/

Many kernel-doc comments in mm/ have the return value descriptions
either misformatted or omitted at all which makes kernel-doc script
unhappy:

$ make V=1 htmldocs
...
./mm/util.c:36: info: Scanning doc for kstrdup
./mm/util.c:41: warning: No description found for return value of 'kstrdup'
./mm/util.c:57: info: Scanning doc for kstrdup_const
./mm/util.c:66: warning: No description found for return value of 'kstrdup_const'
./mm/util.c:75: info: Scanning doc for kstrndup
./mm/util.c:83: warning: No description found for return value of 'kstrndup'
...

Fixing the formatting and adding the missing return value descriptions
eliminates ~100 such warnings.

Link: http://lkml.kernel.org/r/1549549644-4903-4-git-send-email-rppt@linux.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/mm/truncate.c b/mm/truncate.c
index 798e7ccfb030..b7d3c99f00c9 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -539,6 +539,8 @@ EXPORT_SYMBOL(truncate_inode_pages_final);
  * 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)
@@ -664,7 +666,7 @@ static int do_launder_page(struct address_space *mapping, struct page *page)
  * Any pages which are found to be mapped into pagetables are unmapped prior to
  * invalidation.
  *
- * Returns -EBUSY if any pages could not be invalidated.
+ * Return: -EBUSY if any pages could not be invalidated.
  */
 int invalidate_inode_pages2_range(struct address_space *mapping,
                                   pgoff_t start, pgoff_t end)
@@ -761,7 +763,7 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);
  * Any pages which are found to be mapped into pagetables are unmapped prior to
  * invalidation.
  *
- * Returns -EBUSY if any pages could not be invalidated.
+ * Return: -EBUSY if any pages could not be invalidated.
  */
 int invalidate_inode_pages2(struct address_space *mapping)
 {