Re: net/core/xdp.c:725:5: error: no previous declaration for 'bpf_xdp_metadata_rx_timestamp'

[Stanislav Fomichev]

On Fri, Sep 22, 2023 at 9:12 AM kernel test robot <lkp@xxxxxxxxx> wrote:
>
> Hi Stanislav,
>
> FYI, the error/warning still remains.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   27bbf45eae9ca98877a2d52a92a188147cd61b07
> commit: 3d76a4d3d4e591af3e789698affaad88a5a8e8ab bpf: XDP metadata RX kfuncs
> date:   8 months ago
> config: x86_64-sof-customedconfig-avs-defconfig (https://download.01.org/0day-ci/archive/20230923/202309230010.Eio2q6e0-lkp@xxxxxxxxx/config)
> compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230923/202309230010.Eio2q6e0-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/202309230010.Eio2q6e0-lkp@xxxxxxxxx/
>
> All errors (new ones prefixed by >>):
>
> >> net/core/xdp.c:725:5: error: no previous declaration for 'bpf_xdp_metadata_rx_timestamp' [-Werror=missing-declarations]
>     int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
>         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> net/core/xdp.c:737:5: error: no previous declaration for 'bpf_xdp_metadata_rx_hash' [-Werror=missing-declarations]
>     int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash)
>         ^~~~~~~~~~~~~~~~~~~~~~~~
>    cc1: all warnings being treated as errors

I don't think I'm doing anything special for these kfuncs, so, in
theory, the rest of them should also have the same warning.
Should we add another __diag_ignore_all("-Wmissing-declarations", ...)
to kfuncs preamble?
I remember there was a discussion about introducing
BEGIN_KFUNC/END_KFUNC, but I don't think it went anywhere?


> vim +/bpf_xdp_metadata_rx_timestamp +725 net/core/xdp.c
>
>    713
>    714  __diag_push();
>    715  __diag_ignore_all("-Wmissing-prototypes",
>    716                    "Global functions as their definitions will be in vmlinux BTF");
>    717
>    718  /**
>    719   * bpf_xdp_metadata_rx_timestamp - Read XDP frame RX timestamp.
>    720   * @ctx: XDP context pointer.
>    721   * @timestamp: Return value pointer.
>    722   *
>    723   * Returns 0 on success or ``-errno`` on error.
>    724   */
>  > 725  int bpf_xdp_metadata_rx_timestamp(const struct xdp_md *ctx, u64 *timestamp)
>    726  {
>    727          return -EOPNOTSUPP;
>    728  }
>    729
>    730  /**
>    731   * bpf_xdp_metadata_rx_hash - Read XDP frame RX hash.
>    732   * @ctx: XDP context pointer.
>    733   * @hash: Return value pointer.
>    734   *
>    735   * Returns 0 on success or ``-errno`` on error.
>    736   */
>  > 737  int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, u32 *hash)
>    738  {
>    739          return -EOPNOTSUPP;
>    740  }
>    741
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki