Re: [PATCH bpf-next v5 1/6] libbpf: expose resolve_func_ptr() through libbpf_internal.h.

[Kui-Feng Lee <sinquersw@gmail.com>]

On 2/28/24 09:45, Andrii Nakryiko wrote:
> On Mon, Feb 26, 2024 at 5:04 PM Kui-Feng Lee <thinker.li@gmail.com> wrote:
>>
>> bpftool is going to reuse this helper function to support shadow types of
>> struct_ops maps.
>>
>> Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
>> ---
>>   tools/lib/bpf/libbpf.c          | 2 +-
>>   tools/lib/bpf/libbpf_internal.h | 2 ++
>>   2 files changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
>> index 01f407591a92..ef8fd20f33ca 100644
>> --- a/tools/lib/bpf/libbpf.c
>> +++ b/tools/lib/bpf/libbpf.c
>> @@ -2145,7 +2145,7 @@ skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id)
>>          return t;
>>   }
>>
>> -static const struct btf_type *
>> +const struct btf_type *
>>   resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id)
>>   {
>>          const struct btf_type *t;
>> diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
>> index ad936ac5e639..17e6d381da6a 100644
>> --- a/tools/lib/bpf/libbpf_internal.h
>> +++ b/tools/lib/bpf/libbpf_internal.h
>> @@ -234,6 +234,8 @@ struct btf_type;
>>   struct btf_type *btf_type_by_id(const struct btf *btf, __u32 type_id);
>>   const char *btf_kind_str(const struct btf_type *t);
>>   const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id);
>> +/* This function is exposed to bpftool */
>> +const struct btf_type *resolve_func_ptr(const struct btf *btf, __u32 id, __u32 *res_id);
> 
> it's trivial helper, there is no need for bpftool to reuse it, let's
> just implement a local helper for bpftool. We should have done the
> same with skip_mods_and_typedefs() in gen.c, but oh well, we can fix
> that later.
> 
> Generally speaking, I'd like to minimize amount of internal functions
> exposed from libbpf to bpftool. It's justified if the logic is
> non-trivial, but resolve_func_ptr() is not such case.

Ok! I will add an implementation in gen.c

> 
>>
>>   static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t)
>>   {
>> --
>> 2.34.1
>>