Hi Yunjian, kernel test robot noticed the following build warnings: [auto build test WARNING on net-next/main] url: https://github.com/intel-lab-lkp/linux/commits/Yunjian-Wang/xsk-Remove-non-zero-dma_page-check-in-xp_assign_dev/20240124-174011 base: net-next/main patch link: https://lore.kernel.org/r/1706089075-16084-1-git-send-email-wangyunjian%40huawei.com patch subject: [PATCH net-next 2/2] tun: AF_XDP Rx zero-copy support config: s390-defconfig (https://download.01.org/0day-ci/archive/20240128/202401281639.yBaJZ4Sh-lkp@xxxxxxxxx/config) compiler: s390-linux-gcc (GCC) 13.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240128/202401281639.yBaJZ4Sh-lkp@xxxxxxxxx/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-kbuild-all/202401281639.yBaJZ4Sh-lkp@xxxxxxxxx/ All warnings (new ones prefixed by >>): >> drivers/net/tun.c:1298:5: warning: no previous prototype for 'tun_xsk_pool_setup' [-Wmissing-prototypes] 1298 | int tun_xsk_pool_setup(struct net_device *dev, struct xsk_buff_pool *pool, | ^~~~~~~~~~~~~~~~~~ vim +/tun_xsk_pool_setup +1298 drivers/net/tun.c 1297 > 1298 int tun_xsk_pool_setup(struct net_device *dev, struct xsk_buff_pool *pool, 1299 u16 qid) 1300 { 1301 return pool ? tun_xsk_pool_enable(dev, pool, qid) : 1302 tun_xsk_pool_disable(dev, qid); 1303 } 1304 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki