Hi Luigi, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on linux/master] [also build test WARNING on linus/master] [cannot apply to next-20210419] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Luigi-Rizzo/smp-add-a-best_effor... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 5e46d1b78a03d52306f21f77a4e4a144b6d31486 config: riscv-randconfig-r015-20210419 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 2b50f5a4343f8fb06acaa5c36355bcf58092c9cd) 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 riscv cross compiling tool for clang build # apt-get install binutils-riscv64-linux-gnu # https://github.com/0day-ci/linux/commit/9b290e2d29303b7c5bae4a0eddc5bb15c... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Luigi-Rizzo/smp-add-a-best_effort-version-of-smp_call_function_many/20210420-024713 git checkout 9b290e2d29303b7c5bae4a0eddc5bb15c01e72f7 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=riscv 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 >>): * Extended version of smp_call_function_many(). Same constraints. kernel/smp.c:1022: warning: cannot understand function prototype: 'struct smp_call_on_cpu_struct ' vim +722 kernel/smp.c 720 721 /** 723 * @mode == 0 same as wait = false, returns 0; 724 * @mode == 1 same as wait = true, returns 0; 725 * @mode = SMP_CFM_BEST_EFFORT: skips CPUs with previous pending requests, 726 * returns 0 and *mask unmodified if no CPUs are skipped, 727 * -EBUSY if CPUs are skipped, and *mask is the set of skipped CPUs 728 */ 729 int __smp_call_function_many(struct cpumask *mask, smp_call_func_t func, 730 void *info, int mode) 731 { 732 struct cpumask *ret = smp_call_function_many_cond(mask, func, info, 733 mode, NULL); 734 735 if (!ret) 736 return 0; 737 cpumask_andnot(mask, mask, ret); 738 cpumask_and(mask, mask, cpu_online_mask); 739 cpumask_clear_cpu(smp_processor_id(), mask); 740 return -EBUSY; 741 } 742 EXPORT_SYMBOL(__smp_call_function_many); 743 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org