tree: https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git hyperv-next head: 19fd7ca00201c0525452dcf5a490e4b01674ef4c commit: 32be866293fe5355adbf91da1cd612f439fc71e5 [1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM config: x86_64-randconfig-r025-20211216 (https://download.01.org/0day-ci/archive/20211218/202112181133.7Ki4aggA-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 9043c3d65b11b442226015acfbf8167684586cfa) 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://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?... git remote add hyperv https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git git fetch --no-tags hyperv hyperv-next git checkout 32be866293fe5355adbf91da1cd612f439fc71e5 # 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=x86_64 SHELL=/bin/bash kernel/dma/ 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 *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes) ^ kernel/dma/swiotlb.c:166:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes) ^ static 1 warning generated. vim +/swiotlb_mem_remap +166 kernel/dma/swiotlb.c 160 161 /* 162 * Remap swioltb memory in the unencrypted physical address space 163 * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP 164 * Isolation VMs). 165 */ 167 { 168 void *vaddr = NULL; 169 170 if (swiotlb_unencrypted_base) { 171 phys_addr_t paddr = mem->start + swiotlb_unencrypted_base; 172 173 vaddr = memremap(paddr, bytes, MEMREMAP_WB); 174 if (!vaddr) 175 pr_err("Failed to map the unencrypted memory %llx size %lx.\n", 176 paddr, bytes); 177 } 178 179 return vaddr; 180 } 181 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org