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, 18 insertions, 6 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c29828ec9183..4e1d9118ae52 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4816,6 +4816,8 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
  * This function is also limited by MAX_ORDER.
  *
  * Memory allocated by this function must be released by free_pages_exact().
+ *
+ * Return: pointer to the allocated area or %NULL in case of error.
  */
 void *alloc_pages_exact(size_t size, gfp_t gfp_mask)
 {
@@ -4836,6 +4838,8 @@ EXPORT_SYMBOL(alloc_pages_exact);
  *
  * Like alloc_pages_exact(), but try to allocate on node nid first before falling
  * back.
+ *
+ * Return: pointer to the allocated area or %NULL in case of error.
  */
 void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask)
 {
@@ -4869,11 +4873,13 @@ EXPORT_SYMBOL(free_pages_exact);
  * nr_free_zone_pages - count number of pages beyond high watermark
  * @offset: The zone index of the highest zone
  *
- * nr_free_zone_pages() counts the number of counts pages which are beyond the
+ * nr_free_zone_pages() counts the number of pages which are beyond the
  * high watermark within all zones at or below a given zone index.  For each
  * zone, the number of pages is calculated as:
  *
  *     nr_free_zone_pages = managed_pages - high_pages
+ *
+ * Return: number of pages beyond high watermark.
  */
 static unsigned long nr_free_zone_pages(int offset)
 {
@@ -4900,6 +4906,9 @@ static unsigned long nr_free_zone_pages(int offset)
  *
  * nr_free_buffer_pages() counts the number of pages which are beyond the high
  * watermark within ZONE_DMA and ZONE_NORMAL.
+ *
+ * Return: number of pages beyond high watermark within ZONE_DMA and
+ * ZONE_NORMAL.
  */
 unsigned long nr_free_buffer_pages(void)
 {
@@ -4912,6 +4921,8 @@ EXPORT_SYMBOL_GPL(nr_free_buffer_pages);
  *
  * nr_free_pagecache_pages() counts the number of pages which are beyond the
  * high watermark within all zones.
+ *
+ * Return: number of pages beyond high watermark within all zones.
  */
 unsigned long nr_free_pagecache_pages(void)
 {
@@ -5358,7 +5369,8 @@ static int node_load[MAX_NUMNODES];
  * from each node to each node in the system), and should also prefer nodes
  * with no CPUs, since presumably they'll have very little allocation pressure
  * on them otherwise.
- * It returns -1 if no node is found.
+ *
+ * Return: node id of the found node or %NUMA_NO_NODE if no node is found.
  */
 static int find_next_best_node(int node, nodemask_t *used_node_mask)
 {
@@ -6269,7 +6281,7 @@ unsigned long __init __absent_pages_in_range(int nid,
  * @start_pfn: The start PFN to start searching for holes
  * @end_pfn: The end PFN to stop searching for holes
  *
- * It returns the number of pages frames in memory holes within a range.
+ * Return: the number of pages frames in memory holes within a range.
  */
 unsigned long __init absent_pages_in_range(unsigned long start_pfn,
                                                         unsigned long end_pfn)
@@ -6826,7 +6838,7 @@ void __init setup_nr_node_ids(void)
  * model has fine enough granularity to avoid incorrect mapping for the
  * populated node map.
  *
- * Returns the determined alignment in pfn's.  0 if there is no alignment
+ * Return: the determined alignment in pfn's.  0 if there is no alignment
  * requirement (single node).
  */
 unsigned long __init node_map_pfn_alignment(void)
@@ -6881,7 +6893,7 @@ static unsigned long __init find_min_pfn_for_node(int nid)
 /**
  * find_min_pfn_with_active_regions - Find the minimum PFN registered
  *
- * It returns the minimum PFN based on information provided via
+ * Return: the minimum PFN based on information provided via
  * memblock_set_node().
  */
 unsigned long __init find_min_pfn_with_active_regions(void)
@@ -8174,7 +8186,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
  * pageblocks in the range.  Once isolated, the pageblocks should not
  * be modified by others.
  *
- * Returns zero on success or negative error code.  On success all
+ * Return: zero on success or negative error code.  On success all
  * pages which PFN is in [start, end) are allocated for the caller and
  * need to be freed with free_contig_range().
  */