Re: [PATCH bpf-next v3 2/2] selftests/bpf: Update kfuncs using btf_struct_meta to new variants

[Ihor Solodrai <ihor.solodrai@linux.dev>]

On 3/19/26 5:30 AM, Jiri Olsa wrote:
> On Wed, Mar 18, 2026 at 04:42:10PM -0700, Ihor Solodrai wrote:
>> Update selftests to use the new non-_impl kfuncs marked with
>> KF_IMPLICIT_ARGS by removing redundant declarations and macros from
>> bpf_experimental.h (the new kfuncs are present in the vmlinux.h) and
>> updating relevant callsites.
>>
>> Fix spin_lock verifier-log matching for lock_id_kptr_preserve by
>> accepting variable instruction numbers. The calls to kfuncs with
>> implicit arguments do not have register moves (e.g. r5 = 0)
>> corresponding to dummy arguments anymore, so the order of instructions
>> has shifted.
>>
>> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
>> ---
>>  .../testing/selftests/bpf/bpf_experimental.h  | 156 +-----------------
>>  .../selftests/bpf/prog_tests/spin_lock.c      |   5 +-
>>  .../selftests/bpf/progs/kptr_xchg_inline.c    |   4 +-
>>  3 files changed, 9 insertions(+), 156 deletions(-)
>>
>> diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
>> index 44466acf8083..2234bd6bc9d3 100644
>> --- a/tools/testing/selftests/bpf/bpf_experimental.h
>> +++ b/tools/testing/selftests/bpf/bpf_experimental.h
>> @@ -8,156 +8,11 @@
>>  
>>  [...]
>> -
>> -/* Description
>> - *	Free an allocated percpu object. All fields of the object that require
>> - *	destruction will be destructed before the storage is freed.
>> - *
>> - *	The 'meta' parameter is rewritten by the verifier, no need for BPF
>> - *	program to set it.
>> - * Returns
>> - *	Void.
>> - */
>> -extern void bpf_percpu_obj_drop_impl(void *kptr, void *meta) __ksym;
>> +/* Convenience macro to wrap over bpf_percpu_obj_new */
>> +#define bpf_percpu_obj_new(type) ((type __percpu_kptr *)bpf_percpu_obj_new(bpf_core_type_id_local(type)))
> 
> nit, seems like a shame to remove all the comments which are still
> valid, maybe we could leave those externs with comments and just
> drop the _impl suffix

I assumed they were copy-pasted from somewhere, but apparently no.

How about we move the useful comments to kernel/helpers.c, where
the kfuncs are defined?

> 
> jirka