Re: [PATCH] bpf: export btf_find_by_name_kind and bpf_base_func_proto

[Yonghong Song <yonghong.song@linux.dev>]

On 7/25/24 8:45 PM, Ming Lei wrote:
> On Fri, Jul 26, 2024 at 11:21 AM Yonghong Song <yonghong.song@linux.dev> wrote:
>>
>> On 7/24/24 2:13 AM, Ming Lei wrote:
>>> On Tue, Jul 23, 2024 at 09:43:12PM -0700, Kui-Feng Lee wrote:
>>>> On 7/23/24 20:19, Ming Lei wrote:
>>>>> Export btf_find_by_name_kind and bpf_base_func_proto, so that kernel
>>>>> module can use them.
>>>>>
>>>>> Almost all existed struct_ops users(hid, sched_ext, ...) need the two APIs.
>>>>>
>>>>> Without this change, hid-bpf can't be built as module.
>>>> Could you give me more context?
>>>> Give me a link of an example code or something?
>>>> Or explain the use case?
>>> The merged patchset "Registrating struct_ops types from modules" is
>>> trying to allow module to register struct_ops, which often needs
>>> bpf_base_func_proto()(for allowing generic helpers available in
>>> prog) and btf_find_by_name_kind() (for implementing .btf_struct_access).
>>>
>>> One example is hid-bpf, which is a driver and supposed to build as module,
>>> but it can't be done because the two APIs aren't exported.
>> Could you give more specific examples about where these two APIs are
>> used in hid-bpf?
> Sure, hid-bpf struct_ops has been merged to linus tree already.
>
> However, it can't be built as module because the two APIs aren't exported:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/hid/bpf/hid_bpf_struct_ops.c

Okay, From the above hid_bpf_struct_ops.c, I do see bpf_base_func_proto() and
btf_find_by_name_kind() are used.

Your change looks good to me. Please add more details in the commit message and resubmit.
Your subject
    [PATCH] bpf: export btf_find_by_name_kind and bpf_base_func_proto
please change to
    [PATCH bpf-next] bpf: export btf_find_by_name_kind and bpf_base_func_proto

The above 'bpf-next' ensures CI to test your patch.

>
> Thanks,
> Ming
>