[PATCH 14/14] mm/swap: Make NODE_DATA an inline function on CONFIG_FLATMEM

[Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>]

make W=1 generates the following warning in mm/workingset.c for allnoconfig

  mm/workingset.c: In function ‘unpack_shadow’:
  mm/workingset.c:201:15: warning: variable ‘nid’ set but not used [-Wunused-but-set-variable]
    int memcgid, nid;
                 ^~~

On FLATMEM, NODE_DATA returns a global pglist_data without dereferencing
nid. Make the helper an inline function to suppress the warning, add type
checking and to apply any side-effects in the parameter list.

Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
---
 include/linux/mmzone.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 0d53eba1c383..8af2f9ff9737 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1044,7 +1044,10 @@ extern char numa_zonelist_order[];
 #ifndef CONFIG_NEED_MULTIPLE_NODES
 
 extern struct pglist_data contig_page_data;
-#define NODE_DATA(nid)		(&contig_page_data)
+static inline struct pglist_data *NODE_DATA(int nid)
+{
+	return &contig_page_data;
+}
 #define NODE_MEM_MAP(nid)	mem_map
 
 #else /* CONFIG_NEED_MULTIPLE_NODES */
-- 
2.26.2