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From:   Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date:   Wed, 24 Jul 2019 15:51:14 -0400
Message-ID: <CAF=yD-LgN3-a1LtoN+EffvBYzw+7c29AUy5yVGJ1-iBpS0s2=w@mail.gmail.com>
Subject: Re: [PATCH bpf-next 4/6] libbpf: support BPF_MAP_DUMP command
To:     Brian Vazquez <brianvv@google.com>
Cc:     Brian Vazquez <brianvv.kernel@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        "David S . Miller" <davem@davemloft.net>,
        Stanislav Fomichev <sdf@google.com>,
        Willem de Bruijn <willemb@google.com>,
        Petar Penkov <ppenkov@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>
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On Wed, Jul 24, 2019 at 1:10 PM Brian Vazquez <brianvv@google.com> wrote:
>
> Make libbpf aware of new BPF_MAP_DUMP command and add bpf_map_dump and
> bpf_map_dump_flags to use them from the library.
>
> Suggested-by: Stanislav Fomichev <sdf@google.com>
> Signed-off-by: Brian Vazquez <brianvv@google.com>
> ---
>  tools/lib/bpf/bpf.c | 28 ++++++++++++++++++++++++++++
>  tools/lib/bpf/bpf.h |  4 ++++
>  2 files changed, 32 insertions(+)
>
> diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
> index c7d7993c44bb0..c1139b7db756a 100644
> --- a/tools/lib/bpf/bpf.c
> +++ b/tools/lib/bpf/bpf.c
> @@ -368,6 +368,34 @@ int bpf_map_update_elem(int fd, const void *key, const void *value,
>         return sys_bpf(BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));
>  }
>
> +int bpf_map_dump(int fd, const void *prev_key, void *buf, void *buf_len)
> +{
> +       union bpf_attr attr;
> +
> +       memset(&attr, 0, sizeof(attr));
> +       attr.dump.map_fd = fd;
> +       attr.dump.prev_key = ptr_to_u64(prev_key);
> +       attr.dump.buf = ptr_to_u64(buf);
> +       attr.dump.buf_len = ptr_to_u64(buf_len);
> +
> +       return sys_bpf(BPF_MAP_DUMP, &attr, sizeof(attr));
> +}

This can call bpf_map_dump_flags internally to avoid code duplication?

> +
> +int bpf_map_dump_flags(int fd, const void *prev_key, void *buf, void *buf_len,
> +                      __u64 flags)
> +{
> +       union bpf_attr attr;
> +
> +       memset(&attr, 0, sizeof(attr));
> +       attr.dump.map_fd = fd;
> +       attr.dump.prev_key = ptr_to_u64(prev_key);
> +       attr.dump.buf = ptr_to_u64(buf);
> +       attr.dump.buf_len = ptr_to_u64(buf_len);
> +       attr.dump.flags = flags;
> +
> +       return sys_bpf(BPF_MAP_DUMP, &attr, sizeof(attr));
> +}
> +