netdev - Re: [PATCH bpf-next v3 2/4] bpf: factor out helpers to check ctx access for BTF function

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Date:   Sun, 24 Oct 2021 17:27:39 +0800
From:   Hou Tao <houtao1@...wei.com>
To:     Martin KaFai Lau <kafai@...com>
CC:     Alexei Starovoitov <ast@...nel.org>, Yonghong Song <yhs@...com>,
        "Daniel Borkmann" <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>, <netdev@...r.kernel.org>,
        <bpf@...r.kernel.org>
Subject: Re: [PATCH bpf-next v3 2/4] bpf: factor out helpers to check ctx
 access for BTF function

Hi Martin,

On 10/23/2021 8:18 AM, Martin KaFai Lau wrote:
> On Fri, Oct 22, 2021 at 03:55:09PM +0800, Hou Tao wrote:
>> @@ -1649,6 +1649,33 @@ bool bpf_prog_test_check_kfunc_call(u32 kfunc_id, struct module *owner);
>>  bool btf_ctx_access(int off, int size, enum bpf_access_type type,
>>  		    const struct bpf_prog *prog,
>>  		    struct bpf_insn_access_aux *info);
>> +
>> +/*
>> + * The maximum number of BTF function arguments is MAX_BPF_FUNC_ARGS.
>> + * And only aligned read is allowed.
> It is not always 'BTF' function arguments.  Lets remove this comment.
> The function is short and its intention is clear.
Yes, you are right, BTF is not necessary for BPF_PROG_TYPE_RAW_TRACEPOINT program.
I will remove the inaccurate comments and update commit message accordingly.
> Others lgtm.
>
> Acked-by: Martin KaFai Lau <kafai@...com>
Thanks for your detailed suggestions and careful review.

Regards,
Tao