netdev - Re: [PATCH v3 bpf-next 06/18] libbpf: refactor BTF map definition parsing

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Message-ID: <fd61eabd-4205-f173-b67d-c1bb267ee770@fb.com>
Date:   Fri, 23 Apr 2021 11:36:11 -0700
From:   Yonghong Song <yhs@...com>
To:     Andrii Nakryiko <andrii@...nel.org>, <bpf@...r.kernel.org>,
        <netdev@...r.kernel.org>, <ast@...com>, <daniel@...earbox.net>
CC:     <kernel-team@...com>
Subject: Re: [PATCH v3 bpf-next 06/18] libbpf: refactor BTF map definition
 parsing



On 4/23/21 11:13 AM, Andrii Nakryiko wrote:
> Refactor BTF-defined maps parsing logic to allow it to be nicely reused by BPF
> static linker. Further, at least for BPF static linker, it's important to know
> which attributes of a BPF map were defined explicitly, so provide a bit set
> for each known portion of BTF map definition. This allows BPF static linker to
> do a simple check when dealing with extern map declarations.
> 
> The same capabilities allow to distinguish attributes explicitly set to zero
> (e.g., __uint(max_entries, 0)) vs the case of not specifying it at all (no
> max_entries attribute at all). Libbpf is currently not utilizing that, but it
> could be useful for backwards compatibility reasons later.
> 
> Signed-off-by: Andrii Nakryiko <andrii@...nel.org>

Acked-by: Yonghong Song <yhs@...com>