Re: [PATCH bpf-next v7 3/9] selftests/bpf: Move bpf_arena_spin_lock.h to the top level

["Emil Tsalapatis" <emil@etsalapatis.com>]

On Sun Apr 12, 2026 at 3:31 PM EDT, Kumar Kartikeya Dwivedi wrote:
> On Sun, 12 Apr 2026 at 19:45, Emil Tsalapatis <emil@etsalapatis.com> wrote:
>>
>> The bpf_arena_spin_lock.h header is useful for all programs and not
>> just the selftests. Move it to the top level of the BPF selftests
>> to make it more readily accessible.
>>
>
> Please add something to the log to explain why __weak is needed, as
> indicated in https://lore.kernel.org/bpf/CAP01T77GwHgS04TM8yTODyiXh2VJq-=L0FPoRvjpfF4dc6T9zw@mail.gmail.com.

Will do.

>
> Also, since we discussed already, why not move this to libarena?
>

I left it as (imminent) followup work to make libarena completely 
self-contained but it makes sense to add it from the very beginning.
I'll add move the headers in these patches.

>> Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
>> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
>> Acked-by: Song Liu <song@kernel.org>
>> ---
>>  .../selftests/bpf/{progs => }/bpf_arena_spin_lock.h        | 4 ++--
>>  tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c   | 7 -------
>>  tools/testing/selftests/bpf/progs/arena_spin_lock.c        | 2 +-
>>  3 files changed, 3 insertions(+), 10 deletions(-)
>>  rename tools/testing/selftests/bpf/{progs => }/bpf_arena_spin_lock.h (99%)
>>
>> diff --git a/tools/testing/selftests/bpf/progs/bpf_arena_spin_lock.h b/tools/testing/selftests/bpf/bpf_arena_spin_lock.h
>> similarity index 99%
>> rename from tools/testing/selftests/bpf/progs/bpf_arena_spin_lock.h
>> rename to tools/testing/selftests/bpf/bpf_arena_spin_lock.h
>> index f90531cf3ee5..680c9e6cb35d 100644
>> --- a/tools/testing/selftests/bpf/progs/bpf_arena_spin_lock.h
>> +++ b/tools/testing/selftests/bpf/bpf_arena_spin_lock.h
>> @@ -107,7 +107,7 @@ struct arena_qnode {
>>  #define _Q_LOCKED_VAL          (1U << _Q_LOCKED_OFFSET)
>>  #define _Q_PENDING_VAL         (1U << _Q_PENDING_OFFSET)
>>
>> -struct arena_qnode __arena qnodes[_Q_MAX_CPUS][_Q_MAX_NODES];
>> +struct arena_qnode __weak __arena __hidden qnodes[_Q_MAX_CPUS][_Q_MAX_NODES];
>>
>>  static inline u32 encode_tail(int cpu, int idx)
>>  {
>> @@ -240,7 +240,7 @@ static __always_inline int arena_spin_trylock(arena_spinlock_t __arena *lock)
>>         return likely(atomic_try_cmpxchg_acquire(&lock->val, &val, _Q_LOCKED_VAL));
>>  }
>>
>> -__noinline
>> +__noinline __weak
>>  int arena_spin_lock_slowpath(arena_spinlock_t __arena __arg_arena *lock, u32 val)
>>  {
>>         struct arena_mcs_spinlock __arena *prev, *next, *node0, *node;
>> diff --git a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
>> index 693fd86fbde6..acb9d53b5973 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c
>> @@ -5,13 +5,6 @@
>>  #include <sys/sysinfo.h>
>>
>>  struct __qspinlock { int val; };
>> -typedef struct __qspinlock arena_spinlock_t;
>> -
>> -struct arena_qnode {
>> -       unsigned long next;
>> -       int count;
>> -       int locked;
>> -};
>>
>>  #include "arena_spin_lock.skel.h"
>>
>> diff --git a/tools/testing/selftests/bpf/progs/arena_spin_lock.c b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
>> index 086b57a426cf..6c04e7707644 100644
>> --- a/tools/testing/selftests/bpf/progs/arena_spin_lock.c
>> +++ b/tools/testing/selftests/bpf/progs/arena_spin_lock.c
>> @@ -4,7 +4,7 @@
>>  #include <bpf/bpf_tracing.h>
>>  #include <bpf/bpf_helpers.h>
>>  #include "bpf_misc.h"
>> -#include "bpf_arena_spin_lock.h"
>> +#include "../bpf_arena_spin_lock.h"
>>
>>  struct {
>>         __uint(type, BPF_MAP_TYPE_ARENA);
>> --
>> 2.53.0
>>