Hi Stanislav,

[FYI, it's a private test report for your RFC patch.]
[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Stanislav-Fomichev/xdp-hints-via-kfuncs/20221104-113042
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/20221104032532.1615099-13-sdf%40google.com
patch subject: [RFC bpf-next v2 12/14] mxl4: Support rx timestamp metadata for xdp
config: ia64-allyesconfig
compiler: ia64-linux-gcc (GCC) 12.1.0
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/intel-lab-lkp/linux/commit/bb15bd4e2e87117f30c60bbbad15805164454808
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Stanislav-Fomichev/xdp-hints-via-kfuncs/20221104-113042
        git checkout bb15bd4e2e87117f30c60bbbad15805164454808
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=ia64 SHELL=/bin/bash drivers/net/ethernet/broadcom/bnxt/ drivers/net/ethernet/mellanox/mlx4/

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 >>):

   In file included from include/linux/netdevice.h:43,
                    from include/trace/events/xdp.h:8,
                    from include/linux/bpf_trace.h:5,
                    from drivers/net/ethernet/mellanox/mlx4/en_rx.c:35:
   include/net/xdp.h: In function 'xdp_metadata_export_to_skb':
   include/net/xdp.h:448:103: error: 'return' with a value, in function returning void [-Werror=return-type]
     448 | static void xdp_metadata_export_to_skb(const struct bpf_prog *prog, struct bpf_patch *patch) { return 0; }
         |                                                                                                       ^
   include/net/xdp.h:448:13: note: declared here
     448 | static void xdp_metadata_export_to_skb(const struct bpf_prog *prog, struct bpf_patch *patch) { return 0; }
         |             ^~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/net/ethernet/mellanox/mlx4/en_rx.c: At top level:
>> drivers/net/ethernet/mellanox/mlx4/en_rx.c:672:23: warning: no previous prototype for 'mxl4_xdp_rx_timestamp' [-Wmissing-prototypes]
     672 | struct mlx4_xdp_buff *mxl4_xdp_rx_timestamp(struct mlx4_xdp_buff *ctx)
         |                       ^~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/mxl4_xdp_rx_timestamp +672 drivers/net/ethernet/mellanox/mlx4/en_rx.c

   671	
 > 672	struct mlx4_xdp_buff *mxl4_xdp_rx_timestamp(struct mlx4_xdp_buff *ctx)
   673	{
   674		unsigned int seq;
   675		u64 timestamp;
   676		u64 nsec;
   677	
   678		timestamp = mlx4_en_get_cqe_ts(ctx->cqe);
   679	
   680		do {
   681			seq = read_seqbegin(&ctx->mdev->clock_lock);
   682			nsec = timecounter_cyc2time(&ctx->mdev->clock, timestamp);
   683		} while (read_seqretry(&ctx->mdev->clock_lock, seq));
   684	
   685		ctx->r0 = (u64)ns_to_ktime(nsec);
   686		return ctx;
   687	}
   688	

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp