Hi Taehee, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on net-next/master] url: https://github.com/0day-ci/linux/commits/Taehee-Yoo/mld-change-context-fr... base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git 6626a0266566c5aea16178c5e6cd7fc4db3f2f56 config: powerpc64-randconfig-r015-20210209 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project c9439ca36342fb6013187d0a69aef92736951476) 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 # install powerpc64 cross compiling tool for clang build # apt-get install binutils-powerpc64-linux-gnu # https://github.com/0day-ci/linux/commit/9ac7d23c98251efc265073a0d63930c91... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Taehee-Yoo/mld-change-context-from-atomic-to-sleepable/20210209-072339 git checkout 9ac7d23c98251efc265073a0d63930c91739cc02 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): bool mld_check_leave_group(struct ipv6_mc_socklist *mc_lst, int omode) ^ net/ipv6/mcast.c:333:1: note: declare 'static' if the function is not intended to be used outside of this translation unit bool mld_check_leave_group(struct ipv6_mc_socklist *mc_lst, int omode) ^ static 1 warning generated. vim +/mld_check_leave_group +333 net/ipv6/mcast.c 331 332 /* special case - (INCLUDE, empty) == LEAVE_GROUP */ 334 { 335 if (atomic_read(&mc_lst->sl_count) == 1 && omode == MCAST_INCLUDE) 336 return true; 337 else 338 return false; 339 } 340 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org