From: Song Liu <songliubraving@fb.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Andrii Nakryiko <andriin@fb.com>, Alexei Starovoitov <ast@fb.com>,
"daniel@iogearbox.net" <daniel@iogearbox.net>,
Kernel Team <Kernel-team@fb.com>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH bpf-next 1/3] libbpf: capture value in BTF type info for BTF-defined map defs
Date: Thu, 27 Jun 2019 17:55:58 +0000 [thread overview]
Message-ID: <079A7D73-697C-4CFD-97F3-7CFB741BE4C3@fb.com> (raw)
In-Reply-To: <CAEf4Bza1p4ozVV-Vn8ibV6JRtGc_voh-Mkx51eWvuVi1P8ogSA@mail.gmail.com>
> On Jun 27, 2019, at 10:47 AM, Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote:
>
> On Thu, Jun 27, 2019 at 10:27 AM Song Liu <songliubraving@fb.com> wrote:
>>
>>
>>
>>> On Jun 26, 2019, at 4:21 PM, Andrii Nakryiko <andriin@fb.com> wrote:
>>>
>>> Change BTF-defined map definitions to capture compile-time integer
>>> values as part of BTF type definition, to avoid split of key/value type
>>> information and actual type/size/flags initialization for maps.
>>
>> If I have an old bpf program and compiled it with new llvm, will it
>> work with new libbpf?
>
> You mean BPF programs that used previous incarnation of BTF-defined
> maps? No, they won't work. But we never released them, so I think it's
> ok to change them. Nothing should be using that except for selftests,
> which I fixed.
I see. This makes sense.
>
>>
>>
>>>
>>> Signed-off-by: Andrii Nakryiko <andriin@fb.com>
>>> ---
>
> <snip>
>
>>> diff --git a/tools/testing/selftests/bpf/bpf_helpers.h b/tools/testing/selftests/bpf/bpf_helpers.h
>>> index 1a5b1accf091..aa5ddf58c088 100644
>>> --- a/tools/testing/selftests/bpf/bpf_helpers.h
>>> +++ b/tools/testing/selftests/bpf/bpf_helpers.h
>>> @@ -8,6 +8,9 @@
>>> */
>>> #define SEC(NAME) __attribute__((section(NAME), used))
>>>
>>> +#define __int(name, val) int (*name)[val]
>>> +#define __type(name, val) val *name
>>> +
>>
>> I think we need these two in libbpf.
>
> Yes, but it's another story for another set of patches. We'll need to
> provide bpf_helpers as part of libbpf for inclusion into BPF programs,
> but there are a bunch of problems right now with existing
> bpf_heplers.h that prevents us from just copying it into libbpf. We'll
> need to resolve those first.
>
> But then again, there is no use of __int and __type for user-space
> programs, so for now it's ok.
OK. How about we put these two lines in an separate patch?
Thanks,
Song
next prev parent reply other threads:[~2019-06-27 17:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-26 23:21 [PATCH bpf-next 0/3] capture integers in BTF type info for map defs Andrii Nakryiko
2019-06-26 23:21 ` [PATCH bpf-next 1/3] libbpf: capture value in BTF type info for BTF-defined " Andrii Nakryiko
2019-06-27 17:27 ` Song Liu
2019-06-27 17:47 ` Andrii Nakryiko
2019-06-27 17:55 ` Song Liu [this message]
2019-06-27 20:19 ` Andrii Nakryiko
2019-06-26 23:21 ` [PATCH bpf-next 2/3] selftests/bpf: convert selftests using BTF-defined maps to new syntax Andrii Nakryiko
2019-06-26 23:21 ` [PATCH bpf-next 3/3] selftests/bpf: convert legacy BPF maps to BTF-defined ones Andrii Nakryiko
2019-06-27 17:22 ` [PATCH bpf-next 0/3] capture integers in BTF type info for map defs Song Liu
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