On 03/13/20 at 09:42pm, Stephen Rothwell wrote: > Hi all, > > After merging the akpm-current tree, today's linux-next build (x86_64 > allnoconfig) produced this warning: > > mm/sparse.c:311:12: warning: 'fill_subsection_map' defined but not used [-Wunused-function] > 311 | static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > | ^~~~~~~~~~~~~~~~~~~ > mm/sparse.c:306:13: warning: 'is_subsection_map_empty' defined but not used [-Wunused-function] > 306 | static bool is_subsection_map_empty(struct mem_section *ms) > | ^~~~~~~~~~~~~~~~~~~~~~~ > mm/sparse.c:301:12: warning: 'clear_subsection_map' defined but not used [-Wunused-function] > 301 | static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) > | ^~~~~~~~~~~~~~~~~~~~ > > Introduced by commits > > 38eb09ac7c29 ("mm/sparse.c: introduce new function fill_subsection_map()") > 334411156ba6 ("mm/sparse.c: introduce a new function clear_subsection_map()") Hi Stephen, I made below change, but I can't triger these warnings. Could you try below patch, see if it's works? >From 9be668f1e30b6bb4ed5f4a07e7d3bb76d3f58f35 Mon Sep 17 00:00:00 2001 From: Baoquan He <bhe@xxxxxxxxxx> Date: Fri, 13 Mar 2020 20:25:54 +0800 Subject: [PATCH] mm/sparse.c: fix the building warning with !SPARSEMEM Stephen reported below warnings are seen with allnoconfig on x86_64. Fix it by making those dummy functions sub-section map handling visible with CONFIG_SPARSEMEM enabled. mm/sparse.c:311:12: warning: 'fill_subsection_map' defined but not used [-Wunused-function] 311 | static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) | ^~~~~~~~~~~~~~~~~~~ mm/sparse.c:306:13: warning: 'is_subsection_map_empty' defined but not used [-Wunused-function] 306 | static bool is_subsection_map_empty(struct mem_section *ms) | ^~~~~~~~~~~~~~~~~~~~~~~ mm/sparse.c:301:12: warning: 'clear_subsection_map' defined but not used [-Wunused-function] 301 | static int clear_subsection_map(unsigned long pfn, unsigned long nr_pages) | ^~~~~~~~~~~~~~~~~~~~ Signed-off-by: Baoquan He <bhe@xxxxxxxxxx> --- mm/sparse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/sparse.c b/mm/sparse.c index 362018e82e22..9e08d118719f 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -293,7 +293,7 @@ static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) return rc; } -#else +#elif defined(CONFIG_SPARSEMEM) void __init subsection_map_init(unsigned long pfn, unsigned long nr_pages) { } -- 2.17.2