Hi Guixin, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on char-misc/char-misc-testing] [also build test WARNING on mkp-scsi/for-next linux/master linus/master v5.17-rc4 next-20220216] [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/Guixin-Liu/uio-add-ioctl-to-uio/... base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git e6cb9c167eeb8f90ab924666c573e69e85e700a0 config: i386-randconfig-s002 (https://download.01.org/0day-ci/archive/20220217/202202171918.s8P0xa1Y-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.4-dirty # https://github.com/0day-ci/linux/commit/c604d03c2be8ca4b3533bb151bcd2d103... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Guixin-Liu/uio-add-ioctl-to-uio/20220217-103120 git checkout c604d03c2be8ca4b3533bb151bcd2d10379debff # save the config file to linux build tree mkdir build_dir make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=i386 SHELL=/bin/bash drivers/target/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) Please review and possibly fold the followup patch. --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org