Hi Frank, [FYI, it's a private test report for your RFC patch.] [auto build test WARNING on helgaas-pci/next] [also build test WARNING on jonmason-ntb/ntb-next v5.17-rc4 next-20220214] [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/Frank-Li/NTB-function-for-PCIe-R... base: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220215/202202151535.839zuzcU-lk...) compiler: arceb-elf-gcc (GCC) 11.2.0 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/0day-ci/linux/commit/84bf6254010435435a8c196e30bb2d25f... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Frank-Li/NTB-function-for-PCIe-RC-to-EP-connection/20220215-134115 git checkout 84bf6254010435435a8c196e30bb2d25fd22763c # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash drivers/pci/endpoint/functions/ 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 >>): 975 | int pci_read(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val) | ^~~~~~~~ 984 | int pci_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val) | ^~~~~~~~~ vim +/pci_read +975 drivers/pci/endpoint/functions/pci-epf-vntb.c 974 976 { 977 if (devfn == 0) { 978 memcpy(val, ((uint8_t *)pci_space) + where, size); 979 return 0; 980 } 981 return -1; 982 } 983 985 { 986 return 0; 987 } 988 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org