Kernel test robot found[1] commit ccd554f15bb1 ("mm/damon/paddr: support the pageout scheme") on the -mm tree[2], which is introduced by the patch titled 'mm-damon-paddr-support-the-pageout-scheme.patch'[3] introduces following build warning, and therefore the build fails if 'CONFIG_WERROR=y'. linux/mm/damon/paddr.c:216:5: error: no previous prototype for ‘damon_pa_apply_scheme’ [-Werror=missing-prototypes] int damon_pa_apply_scheme(struct damon_ctx *ctx, struct damon_target *t, ^~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors linux/scripts/Makefile.build:277: recipe for target 'mm/damon/paddr.o' failed This commit fixes the warning by adding the missed prototype in the header file. Note: Because the reported '.config' introduces warnings on not only DAMON but also other subsystems, I tested for only DAMON by adding the below compiler flag in mm/damon/Makefile. ccflags-$(CONFIG_DAMON_PADDR) += -Werror -Wmissing-prototypes [1] https://lore.kernel.org/lkml/202110250029.5rftt73s-lkp@intel.com/ [2] https://github.com/hnaz/linux-mm/commit/ccd554f15bb1cd977d740c1ea8241ecf9... [3] https://lore.kernel.org/mm-commits/20211019213137.91_rr1GrX%25akpm@linux-... Fixes: ccd554f15bb1 ("mm/damon/paddr: support the pageout scheme") in -mm tree Reported-by: kernel test robot <lkp(a)intel.com&gt; Signed-off-by: SeongJae Park <sj(a)kernel.org&gt; --- include/linux/damon.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/damon.h b/include/linux/damon.h index 715dadd21f7c..9a327bc787b5 100644 --- a/include/linux/damon.h +++ b/include/linux/damon.h @@ -357,6 +357,8 @@ void damon_va_set_primitives(struct damon_ctx *ctx); void damon_pa_prepare_access_checks(struct damon_ctx *ctx); unsigned int damon_pa_check_accesses(struct damon_ctx *ctx); bool damon_pa_target_valid(void *t); +int damon_pa_apply_scheme(struct damon_ctx *context, struct damon_target *t, + struct damon_region *r, struct damos *scheme); void damon_pa_set_primitives(struct damon_ctx *ctx); #endif /* CONFIG_DAMON_PADDR */ -- 2.17.1