tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 79e06c4c4950be2abd8ca5d2428a8c915aa62c24 commit: d552ddeaab4a15a8dc157ac007833aa0b3706862 MIPS: bmips: Remove obsolete DMA mapping support date: 5 days ago config: mips-bmips_stb_defconfig (https://download.01.org/0day-ci/archive/20220117/202201170455.DlrxW9Pv-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project c63a3175c2947e8c1a2d3bbe16a8586600705c54) 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 mips cross compiling tool for clang build # apt-get install binutils-mips-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout d552ddeaab4a15a8dc157ac007833aa0b3706862 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash arch/mips/bmips/ 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 >>): void arch_sync_dma_for_cpu_all(void) ^ arch/mips/bmips/dma.c:7:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void arch_sync_dma_for_cpu_all(void) ^ static 1 warning generated. vim +/arch_sync_dma_for_cpu_all +7 arch/mips/bmips/dma.c d666cd0246f78b arch/mips/bcm3384/dma.c Kevin Cernekee 2014-10-20 6 56e35f9c5b87ec arch/mips/bmips/dma.c Christoph Hellwig 2019-11-07 @7 void arch_sync_dma_for_cpu_all(void) :::::: The code at line 7 was first introduced by commit :::::: 56e35f9c5b87ec1ae93e483284e189c84388de16 dma-mapping: drop the dev argument to arch_sync_dma_for_* :::::: TO: Christoph Hellwig <hch(a)lst.de&gt; :::::: CC: Christoph Hellwig <hch(a)lst.de&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org