Re: [PATCH bpf-next v8 5/9] bpftool: Generate skeleton for global percpu data

[Leon Hwang]

On 2/7/26 03:32, Andrii Nakryiko wrote:
> On Wed, Jul 1, 2026 at 9:49 AM Quentin Monnet <qmo@xxxxxxxxxx> wrote:
>>
>> 2026-06-29 23:24 UTC+0800 ~ Leon Hwang <leon.hwang@xxxxxxxxx>
[...]
>>> @@ -254,6 +254,20 @@ static const struct btf_type *find_type_for_map(struct btf *btf, const char *map
>>>       return NULL;
>>>  }
>>>
>>> +static bool bpf_map_is_skel_data(const struct bpf_map *map)
>>> +{
>>> +     if (!bpf_map__is_internal(map))
>>> +             return false;
>>> +
>>> +     if (bpf_map__map_flags(map) & BPF_F_MMAPABLE)
>>> +             return true;
>>> +
>>> +     if (bpf_map__type(map) == BPF_MAP_TYPE_PERCPU_ARRAY)
>>> +             return true;
>>> +
>>> +     return false;
>>> +}
>>> +
>>>  static bool is_mmapable_map(const struct bpf_map *map, char *buf, size_t sz)
>>>  {
>>>       size_t tmp_sz;
>>> @@ -263,7 +277,7 @@ static bool is_mmapable_map(const struct bpf_map *map, char *buf, size_t sz)
>>>               return true;
>>>       }
>>>
>>> -     if (!bpf_map__is_internal(map) || !(bpf_map__map_flags(map) & BPF_F_MMAPABLE))
>>> +     if (!bpf_map_is_skel_data(map))
>>>               return false;
>>>
>>>       if (!get_map_ident(map, buf, sz))
>>
>>
>> Thanks! The bpftool patch looks good, with one reservation: after this
>> patch, I believe "is_mmapable_map(map, ...)" will return true if map is
>> a percpu map, although percpu maps aren't mmap-able, so we should
>> probably update the name of that function to avoid any confusion?
>>
> 
> Great observation, Quentin!
> 
> bpf_map_is_skel_data() I think was supposed to be exactly that generic
> name. But it seems like Leon went half-way through with unification.
> Unless there are some subtle situations where per-cpu array shouldn't
> be handled where is_mmapable_map() is handled, we should rename
> is_mmapable_map() and add BPF_MAP_TYPE_PERCPU_ARRAY check (assuming
> it's internal map, of course) there.
> 
> Leon, can you please check?
> 
Aha, my bad.

Try to rename is_mmapable_map() to bpf_map_is_skel_data(). See below patch.

Thanks,
Leon

---