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From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Quentin Monnet <quentin@isovalent.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>, bpf <bpf@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next v3 2/3] tools: bpftool: keep errors for map-of-map dumps if distinct from ENOENT
Date: Thu, 10 Sep 2020 09:42:36 -0700	[thread overview]
Message-ID: <CAEf4BzZpp7Rfg5N-1G570NQ1FqKjthpeiuWkNUn-uXQv9Gx8Vg@mail.gmail.com> (raw)
In-Reply-To: <20200910102652.10509-3-quentin@isovalent.com>

On Thu, Sep 10, 2020 at 3:27 AM Quentin Monnet <quentin@isovalent.com> wrote:
>
> When dumping outer maps or prog_array maps, and on lookup failure,
> bpftool simply skips the entry with no error message. This is because
> the kernel returns non-zero when no value is found for the provided key,
> which frequently happen for those maps if they have not been filled.
>
> When such a case occurs, errno is set to ENOENT. It seems unlikely we
> could receive other error codes at this stage (we successfully retrieved
> map info just before), but to be on the safe side, let's skip the entry
> only if errno was ENOENT, and not for the other errors.
>
> v3: New patch
>
> Signed-off-by: Quentin Monnet <quentin@isovalent.com>
> ---
>  tools/bpf/bpftool/map.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c
> index c8159cb4fb1e..d8581d5e98a1 100644
> --- a/tools/bpf/bpftool/map.c
> +++ b/tools/bpf/bpftool/map.c
> @@ -240,8 +240,8 @@ print_entry_error(struct bpf_map_info *map_info, void *key, int lookup_errno)
>          * means there is no entry for that key. Do not print an error message
>          * in that case.
>          */
> -       if (map_is_map_of_maps(map_info->type) ||
> -           map_is_map_of_progs(map_info->type))
> +       if ((map_is_map_of_maps(map_info->type) ||
> +            map_is_map_of_progs(map_info->type)) && lookup_errno == ENOENT)
>                 return;


Ah, ok, you decided to split it out into a separate patch. Ok.

Acked-by: Andrii Nakryiko <andriin@fb.com>

>
>         if (json_output) {
> --
> 2.25.1
>

  reply	other threads:[~2020-09-10 16:43 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-10 10:26 [PATCH bpf-next v3 0/2] tools: bpftool: support creating outer maps Quentin Monnet
2020-09-10 10:26 ` [PATCH bpf-next v3 1/3] tools: bpftool: clean up function to dump map entry Quentin Monnet
2020-09-10 16:41   ` Andrii Nakryiko
2020-09-10 16:43     ` Andrii Nakryiko
2020-09-10 10:26 ` [PATCH bpf-next v3 2/3] tools: bpftool: keep errors for map-of-map dumps if distinct from ENOENT Quentin Monnet
2020-09-10 16:42   ` Andrii Nakryiko [this message]
2020-09-10 16:45     ` Quentin Monnet
2020-09-10 10:26 ` [PATCH bpf-next v3 3/3] tools: bpftool: add "inner_map" to "bpftool map create" outer maps Quentin Monnet
2020-09-11  0:30 ` [PATCH bpf-next v3 0/2] tools: bpftool: support creating " Alexei Starovoitov

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