[luxis1999-iommufd:iommufd-v5.17-rc4 29/31] vfio.c:undefined reference to `iommufd_vfio_check_extension'

[kernel test robot]

tree:   https://github.com/luxis1999/iommufd iommufd-v5.17-rc4
head:   d0e769d6ae11d7abe38d2f0598926ba499bf3ec1
commit: d1878386aaf2b9c574b6ceafc7437ddd2152f926 [29/31] vfio: Fix kernel panic in vfio_external_check_extension()
config: arc-randconfig-r043-20220313 (https://download.01.org/0day-ci/archive/20220313/202203130530.K8aEny7T-lkp@xxxxxxxxx/config)
compiler: arc-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/luxis1999/iommufd/commit/d1878386aaf2b9c574b6ceafc7437ddd2152f926
        git remote add luxis1999-iommufd https://github.com/luxis1999/iommufd
        git fetch --no-tags luxis1999-iommufd iommufd-v5.17-rc4
        git checkout d1878386aaf2b9c574b6ceafc7437ddd2152f926
        # 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

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   arc-elf-ld: drivers/vfio/vfio.o: in function `vfio_external_check_extension':
>> vfio.c:(.text+0x7c8): undefined reference to `iommufd_vfio_check_extension'
>> arc-elf-ld: vfio.c:(.text+0x7c8): undefined reference to `iommufd_vfio_check_extension'
   arc-elf-ld: drivers/vfio/vfio.o: in function `__vfio_group_unset_container':
   vfio.c:(.text+0x8fa): undefined reference to `vfio_group_unset_iommufd'
   arc-elf-ld: vfio.c:(.text+0x8fa): undefined reference to `vfio_group_unset_iommufd'
   arc-elf-ld: drivers/vfio/vfio.o: in function `vfio_group_set_container':
   vfio.c:(.text+0x1180): undefined reference to `vfio_group_set_iommufd'
   arc-elf-ld: vfio.c:(.text+0x1180): undefined reference to `vfio_group_set_iommufd'

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0-DAY CI Kernel Test Service
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx