linux-kernel - Re: [RFC PATCH v3 3/3] btf: Reuse libbpf code for BTF type sorting verification and binary search

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Message-ID: <CAEf4BzZ+tpT2ViD_zc8mwz260spriYDiPymw3MFsEibRcuqbqg@mail.gmail.com>
Date: Tue, 28 Oct 2025 11:40:03 -0700
From: Andrii Nakryiko <andrii.nakryiko@...il.com>
To: Donglin Peng <dolinux.peng@...il.com>
Cc: ast@...nel.org, linux-kernel@...r.kernel.org, bpf@...r.kernel.org, 
	Eduard Zingerman <eddyz87@...il.com>, Alan Maguire <alan.maguire@...cle.com>, Song Liu <song@...nel.org>, 
	pengdonglin <pengdonglin@...omi.com>
Subject: Re: [RFC PATCH v3 3/3] btf: Reuse libbpf code for BTF type sorting
 verification and binary search

On Mon, Oct 27, 2025 at 6:54 AM Donglin Peng <dolinux.peng@...il.com> wrote:
>
> The previous commit implemented BTF sorting verification and binary
> search algorithm in libbpf. This patch enables this functionality in
> the kernel.
>
> Cc: Eduard Zingerman <eddyz87@...il.com>
> Cc: Alexei Starovoitov <ast@...nel.org>
> Cc: Andrii Nakryiko <andrii.nakryiko@...il.com>
> Cc: Alan Maguire <alan.maguire@...cle.com>
> Cc: Song Liu <song@...nel.org>
> Signed-off-by: pengdonglin <pengdonglin@...omi.com>
> Signed-off-by: Donglin Peng <dolinux.peng@...il.com>
> ---
> v2->v3:
> - Include btf_sort.c directly in btf.c to reduce function call overhead
> ---
>  kernel/bpf/btf.c | 34 ++++++++++++++++++----------------
>  1 file changed, 18 insertions(+), 16 deletions(-)
>
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 0de8fc8a0e0b..df258815a6ca 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -33,6 +33,7 @@
>  #include <net/sock.h>
>  #include <net/xdp.h>
>  #include "../tools/lib/bpf/relo_core.h"
> +#include "../tools/lib/bpf/btf_sort.h"

I don't believe in code reuse for the sake of code reuse. This code
sharing just makes everything more entangled and complicated.
Reimplementing binary search is totally fine, IMO.

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