Re: [PATCH bpf-next v5 08/17] bpf: Support consuming XDP HW metadata from fext programs

[Martin KaFai Lau <martin.lau@linux.dev>]

On 12/22/22 8:06 PM, Stanislav Fomichev wrote:
>>> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
>>> index 11c558be4992..64a68e8fb072 100644
>>> --- a/kernel/bpf/syscall.c
>>> +++ b/kernel/bpf/syscall.c
>>> @@ -2605,6 +2605,12 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
>>>                        goto free_prog_sec;
>>>        }
>>>
>>> +     if (type == BPF_PROG_TYPE_EXT && dst_prog) {
>> Does it also need to test the bpf_prog_is_dev_bound(dst_prog->aux)?  Otherwise,
>> the bpf_prog_dev_bound_inherit() below will fail on everything for !CONFIG_NET.
> We do the following in bpf_prog_dev_bound_inherit which should be enough?
> 
> if (!bpf_prog_is_dev_bound(old_prog->aux))
>       return 0;
> 
> Or am I missing something?

The inline one in include/linux/bpf.h will be called instead when CONFIG_NET is 
not set:

static inline int bpf_prog_dev_bound_inherit(struct bpf_prog *new_prog,
					     struct bpf_prog *old_prog)
{
	return -EOPNOTSUPP;
}