Re: [sj:damon/next 52/104] mm/memory.c:6046:3: error: call to undeclared function 'damon_report_access'; ISO C99 and later do not support implicit function declarations

[SeongJae Park <sj@kernel.org>]

Hello,

On Sat, 19 Jul 2025 21:05:04 +0800 kernel test robot <lkp@intel.com> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/sj/linux.git damon/next
> head:   587ffe894dbc4bdb791e375c50e446a32fba081a
> commit: cd52442f08196fc17179dc9a95b097df531203b7 [52/104] mm/memory: report fault information to DAMON
> config: i386-buildonly-randconfig-001-20250719 (https://download.01.org/0day-ci/archive/20250719/202507192010.91NbXIjJ-lkp@intel.com/config)
> compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250719/202507192010.91NbXIjJ-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202507192010.91NbXIjJ-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
> >> mm/memory.c:6046:3: error: call to undeclared function 'damon_report_access'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     6046 |                 damon_report_access(&access_report);
>          |                 ^
>    mm/memory.c:6176:5: error: call to undeclared function 'damon_report_access'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     6176 |                                 damon_report_access(&access_report);
>          |                                 ^
>    2 errors generated.

Thank you for this report!  I just pushed below fix as
http://git.kernel.org/sj/c/5559267d916c.


Thanks,
SJ

===== >8 =====
Author: SeongJae Park <sj@kernel.org>
Date:   Sat Jul 19 09:58:13 2025 -0700

    mm/damon: implement static inline fake damon_report_access for !CONFIG_DAMON

    Reported-by: kernel test robot <lkp@intel.com>
    Closes: https://lore.kernel.org/oe-kbuild-all/202507192010.91NbXIjJ-lkp@intel.com/
    Signed-off-by: SeongJae Park <sj@kernel.org>

diff --git a/include/linux/damon.h b/include/linux/damon.h
index 8f6d370754c7..96f9d8c6fe0c 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -977,6 +977,13 @@ void damon_report_access(struct damon_access_report *report);
 int damon_set_region_biggest_system_ram_default(struct damon_target *t,
                                unsigned long *start, unsigned long *end);

+#else  /* CONFIG_DAMON */
+
+static inline void damon_report_access(struct damon_access_report *report)
+{
+       return;
+}
+
 #endif /* CONFIG_DAMON */

 #endif /* _DAMON_H */