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Date:   Fri, 1 Apr 2022 17:05:07 +0100
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Subject: Re: [PATCH bpf-next 3/3] bpf/bpftool: handle libbpf_probe_prog_type
 errors
Content-Language: en-GB
To:     Milan Landaverde <milan@mdaverde.com>, bpf@vger.kernel.org
Cc:     ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
        kafai@fb.com, songliubraving@fb.com, yhs@fb.com,
        john.fastabend@gmail.com, kpsingh@kernel.org,
        davemarchevsky@fb.com, sdf@google.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20220331154555.422506-1-milan@mdaverde.com>
 <20220331154555.422506-4-milan@mdaverde.com>
From:   Quentin Monnet <quentin@isovalent.com>
In-Reply-To: <20220331154555.422506-4-milan@mdaverde.com>
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2022-03-31 11:45 UTC-0400 ~ Milan Landaverde <milan@mdaverde.com>
> Previously [1], we were using bpf_probe_prog_type which returned a
> bool, but the new libbpf_probe_bpf_prog_type can return a negative
> error code on failure. This change decides for bpftool to declare
> a program type is not available on probe failure.
> 
> [1] https://lore.kernel.org/bpf/20220202225916.3313522-3-andrii@kernel.org/
> 
> Signed-off-by: Milan Landaverde <milan@mdaverde.com>
> ---
>  tools/bpf/bpftool/feature.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
> index c2f43a5d38e0..b2fbaa7a6b15 100644
> --- a/tools/bpf/bpftool/feature.c
> +++ b/tools/bpf/bpftool/feature.c
> @@ -564,7 +564,7 @@ probe_prog_type(enum bpf_prog_type prog_type, bool *supported_types,
>  
>  		res = probe_prog_type_ifindex(prog_type, ifindex);
>  	} else {
> -		res = libbpf_probe_bpf_prog_type(prog_type, NULL);
> +		res = libbpf_probe_bpf_prog_type(prog_type, NULL) > 0;
>  	}
>  
>  #ifdef USE_LIBCAP

Reviewed-by: Quentin Monnet <quentin@isovalent.com>

Thanks!