Hi Xuan,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Xuan-Zhuo/virtio-net-support-xdp-socket-zero-copy/20210617-033438
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git c7654495916e109f76a67fd3ae68f8fa70ab4faa
config: i386-randconfig-a004-20210620 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/0day-ci/linux/commit/f5f1e60139e7c38fbb4ed58d503e89bbb26c1464
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Xuan-Zhuo/virtio-net-support-xdp-socket-zero-copy/20210617-033438
        git checkout f5f1e60139e7c38fbb4ed58d503e89bbb26c1464
        # save the attached .config to linux build tree
        make W=1 ARCH=i386 

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

All errors (new ones prefixed by >>, old ones prefixed by <<):

ERROR: modpost: missing MODULE_LICENSE() in drivers/net/virtio/xsk.o
ERROR: modpost: "merge_drop_follow_bufs" [drivers/net/virtio/xsk.ko] undefined!
ERROR: modpost: "virtnet_run_xdp" [drivers/net/virtio/xsk.ko] undefined!
ERROR: modpost: "merge_receive_follow_bufs" [drivers/net/virtio/xsk.ko] undefined!
ERROR: modpost: "virtnet_xsk_wakeup" [drivers/net/virtio/virtio_net.ko] undefined!
ERROR: modpost: "receive_xsk" [drivers/net/virtio/virtio_net.ko] undefined!
ERROR: modpost: "add_recvbuf_xsk" [drivers/net/virtio/virtio_net.ko] undefined!
ERROR: modpost: "virtnet_poll_xsk" [drivers/net/virtio/virtio_net.ko] undefined!
>> ERROR: modpost: "virtqueue_detach_unused_buf_ctx" [drivers/net/virtio/virtio_net.ko] undefined!
ERROR: modpost: "virtnet_xsk_ctx_rx_copy" [drivers/net/virtio/virtio_net.ko] undefined!
ERROR: modpost: "virtnet_xsk_complete" [drivers/net/virtio/virtio_net.ko] undefined!
WARNING: modpost: suppressed 1 unresolved symbol warnings because there were too many)

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