Hi Yu, Thank you for the patch! Yet something to improve: [auto build test ERROR on next-20220916] url: https://github.com/intel-lab-lkp/linux/commits/Yu-Kuai/blk-wbt-simple-improvment-to-enable-wbt-correctly/20220919-094019 base: d5538ab91d3a9a237805be6f8c6c272af2987995 config: x86_64-randconfig-a001-20220919 (https://download.01.org/0day-ci/archive/20220919/202209191345.OaqfJF8y-lkp@xxxxxxxxx/config) compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1) 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/dd5a7be692b8fc9794f29648d0805a2d65b9c4de git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Yu-Kuai/blk-wbt-simple-improvment-to-enable-wbt-correctly/20220919-094019 git checkout dd5a7be692b8fc9794f29648d0805a2d65b9c4de # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@xxxxxxxxx> All errors (new ones prefixed by >>): >> block/blk-sysfs.c:475:8: error: implicit declaration of function 'wbt_disabled' is invalid in C99 [-Werror,-Wimplicit-function-declaration] lat = wbt_disabled(q) ? 0 : div_u64(wbt_get_min_lat(q), 1000); ^ block/blk-sysfs.c:500:6: error: implicit declaration of function 'wbt_disabled' is invalid in C99 [-Werror,-Wimplicit-function-declaration] if (wbt_disabled(q)) ^ 2 errors generated. vim +/wbt_disabled +475 block/blk-sysfs.c 467 468 static ssize_t queue_wb_lat_show(struct request_queue *q, char *page) 469 { 470 u64 lat; 471 472 if (!wbt_rq_qos(q)) 473 return -EINVAL; 474 > 475 lat = wbt_disabled(q) ? 0 : div_u64(wbt_get_min_lat(q), 1000); 476 477 return sprintf(page, "%llu\n", lat); 478 } 479 -- 0-DAY CI Kernel Test Service https://01.org/lkp