Hi Hangbin,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on bpf-next/master]
[also build test WARNING on bpf/master net/master net-next/master linus/master v5.7-rc1 next-20200415]
[cannot apply to ipvs/master]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Hangbin-Liu/xdp-add-dev-map-multicast-support/20200416-024427
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

   In file included from include/linux/bpf-cgroup.h:5:0,
                    from include/linux/cgroup-defs.h:22,
                    from include/linux/cgroup.h:28,
                    from include/linux/memcontrol.h:13,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   include/linux/bpf.h: In function 'array_of_map_lookup_elem':
>> include/linux/bpf.h:1288:1: warning: no return statement in function returning non-void [-Wreturn-type]
    }
    ^
   include/linux/bpf.h: In function 'htab_of_map_lookup_elem':
   include/linux/bpf.h:1293:1: warning: no return statement in function returning non-void [-Wreturn-type]
    }
    ^
   In file included from include/linux/bpf-cgroup.h:5:0,
                    from include/linux/cgroup-defs.h:22,
                    from include/linux/cgroup.h:28,
                    from include/linux/memcontrol.h:13,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   At top level:
   include/linux/bpf.h:1290:14: warning: 'htab_of_map_lookup_elem' defined but not used [-Wunused-function]
    static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
                 ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/bpf.h:1285:14: warning: 'array_of_map_lookup_elem' defined but not used [-Wunused-function]
    static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
                 ^~~~~~~~~~~~~~~~~~~~~~~~
--
   In file included from include/linux/bpf-cgroup.h:5:0,
                    from include/linux/cgroup-defs.h:22,
                    from include/linux/cgroup.h:28,
                    from include/linux/memcontrol.h:13,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   include/linux/bpf.h: In function 'array_of_map_lookup_elem':
>> include/linux/bpf.h:1288:1: warning: no return statement in function returning non-void [-Wreturn-type]
    }
    ^
   include/linux/bpf.h: In function 'htab_of_map_lookup_elem':
   include/linux/bpf.h:1293:1: warning: no return statement in function returning non-void [-Wreturn-type]
    }
    ^
   In file included from include/linux/bpf-cgroup.h:5:0,
                    from include/linux/cgroup-defs.h:22,
                    from include/linux/cgroup.h:28,
                    from include/linux/memcontrol.h:13,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   At top level:
   include/linux/bpf.h:1290:14: warning: 'htab_of_map_lookup_elem' defined but not used [-Wunused-function]
    static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key)
                 ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/bpf.h:1285:14: warning: 'array_of_map_lookup_elem' defined but not used [-Wunused-function]
    static void *array_of_map_lookup_elem(struct bpf_map *map, void *key)
                 ^~~~~~~~~~~~~~~~~~~~~~~~
   22 real  4 user  6 sys  50.68% cpu 	make prepare

vim +1288 include/linux/bpf.h

  1287	
> 1288	}
  1289	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org