Hi Stanislav,

I love your patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Stanislav-Fomichev/xdp-hints-via-kfuncs/20221122-022956
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20221121182552.2152891-3-sdf%40google.com
patch subject: [PATCH bpf-next v2 2/8] bpf: XDP metadata RX kfuncs
config: i386-randconfig-a013
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
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/intel-lab-lkp/linux/commit/f402227f5d69dc73c19606ed3fdba8f48267e1ad
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Stanislav-Fomichev/xdp-hints-via-kfuncs/20221122-022956
        git checkout f402227f5d69dc73c19606ed3fdba8f48267e1ad
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash net/core/

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

All warnings (new ones prefixed by >>):

   net/core/xdp.c:714:15: warning: no previous prototype for function 'bpf_xdp_metadata_rx_timestamp_supported' [-Wmissing-prototypes]
   noinline bool bpf_xdp_metadata_rx_timestamp_supported(const struct xdp_md *ctx)
                 ^
   net/core/xdp.c:714:10: note: declare 'static' if the function is not intended to be used outside of this translation unit
   noinline bool bpf_xdp_metadata_rx_timestamp_supported(const struct xdp_md *ctx)
            ^
            static 
   net/core/xdp.c:719:14: warning: no previous prototype for function 'bpf_xdp_metadata_rx_timestamp' [-Wmissing-prototypes]
   noinline u64 bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx)
                ^
   net/core/xdp.c:719:10: note: declare 'static' if the function is not intended to be used outside of this translation unit
   noinline u64 bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx)
            ^
            static 
>> net/core/xdp.c:724:15: warning: no previous prototype for function 'bpf_xdp_metadata_rx_hash_supported' [-Wmissing-prototypes]
   noinline bool bpf_xdp_metadata_rx_hash_supported(const struct xdp_md *ctx)
                 ^
   net/core/xdp.c:724:10: note: declare 'static' if the function is not intended to be used outside of this translation unit
   noinline bool bpf_xdp_metadata_rx_hash_supported(const struct xdp_md *ctx)
            ^
            static 
>> net/core/xdp.c:729:14: warning: no previous prototype for function 'bpf_xdp_metadata_rx_hash' [-Wmissing-prototypes]
   noinline u32 bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx)
                ^
   net/core/xdp.c:729:10: note: declare 'static' if the function is not intended to be used outside of this translation unit
   noinline u32 bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx)
            ^
            static 
   4 warnings generated.


vim +/bpf_xdp_metadata_rx_hash_supported +724 net/core/xdp.c

   723	
 > 724	noinline bool bpf_xdp_metadata_rx_hash_supported(const struct xdp_md *ctx)
   725	{
   726		return false;
   727	}
   728	
 > 729	noinline u32 bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx)
   730	{
   731		return 0;
   732	}
   733	

-- 
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