Hi "Björn,

I love your patch! Yet something to improve:

[auto build test ERROR on 7b1e385c9a488de9291eaaa412146d3972e9dec5]

url:    https://github.com/0day-ci/linux/commits/Bj-rn-T-pel/Optimize-bpf_redirect_map-xdp_do_redirect/20210220-233623
base:   7b1e385c9a488de9291eaaa412146d3972e9dec5
config: s390-randconfig-m031-20210221 (attached as .config)
compiler: s390-linux-gcc (GCC) 9.3.0
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/3995bc7a37a3a7975c4a04f668408d5aa31cbe37
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Bj-rn-T-pel/Optimize-bpf_redirect_map-xdp_do_redirect/20210220-233623
        git checkout 3995bc7a37a3a7975c4a04f668408d5aa31cbe37
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=s390 

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

All errors (new ones prefixed by >>):

   s390-linux-ld: kernel/bpf/verifier.o: in function `fixup_bpf_calls':

quoted

verifier.c:(.text+0xa4fc): undefined reference to `get_xdp_redirect_func'

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