Hi Ho-Ren,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Ho-Ren-Jack-Chuang/Add-BPF-htab-map-s-used-size-for-monitoring/20221105-105421
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20221105025146.238209-2-horenchuang%40bytedance.com
patch subject: [PATCH bpf-next v1 1/4] bpf: Support reporting BPF htab map's used size for monitoring
config: m68k-allyesconfig
compiler: m68k-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/3188e1adf82d93738d5e5496ee87bbd9411d8465
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Ho-Ren-Jack-Chuang/Add-BPF-htab-map-s-used-size-for-monitoring/20221105-105421
        git checkout 3188e1adf82d93738d5e5496ee87bbd9411d8465
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=m68k SHELL=/bin/bash kernel/bpf/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> kernel/bpf/hashtab.c:2181:5: warning: no previous prototype for 'htab_map_get_used_elem' [-Wmissing-prototypes]
    2181 | u32 htab_map_get_used_elem(struct bpf_map *map)
         |     ^~~~~~~~~~~~~~~~~~~~~~


vim +/htab_map_get_used_elem +2181 kernel/bpf/hashtab.c

  2180	
> 2181	u32 htab_map_get_used_elem(struct bpf_map *map)
  2182	{
  2183		struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
  2184	
  2185		/* The elem count may temporarily go beyond the max after
  2186		 * inc_elem_count() but before dec_elem_count().
  2187		 */
  2188		if (htab->use_percpu_counter)
  2189			return min_t(u32, htab->map.max_entries,
  2190					percpu_counter_sum(&htab->pcount) +
  2191								atomic_read(&htab->count));
  2192		else
  2193			return min_t(u32, htab->map.max_entries,
  2194								atomic_read(&htab->count));
  2195	}
  2196	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp