From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andriin@fb.com>, bpf <bpf@vger.kernel.org>,
Networking <netdev@vger.kernel.org>,
Alexei Starovoitov <ast@fb.com>, Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 2/6] libbpf: move bpf_helpers.h, bpf_endian.h into libbpf
Date: Tue, 1 Oct 2019 16:40:01 -0700 [thread overview]
Message-ID: <CAEf4BzZ-OoJxdk3RkB6JyYiNGMcO9Odgtq12Z3j8iu2cmq0F7g@mail.gmail.com> (raw)
In-Reply-To: <CAEf4BzZQ=NNK42yOu7_H+yuqZ_1npBxDaTuQwsrmJoQUiMfd7A@mail.gmail.com>
On Tue, Oct 1, 2019 at 4:31 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Tue, Oct 1, 2019 at 3:45 PM Daniel Borkmann <daniel@iogearbox.net> wrote:
> >
> > On Mon, Sep 30, 2019 at 11:58:51AM -0700, Andrii Nakryiko wrote:
> > > Make bpf_helpers.h and bpf_endian.h official part of libbpf. Ensure they
> > > are installed along the other libbpf headers.
> > >
> > > Signed-off-by: Andrii Nakryiko <andriin@fb.com>
> >
> > [...]
[...]
> >
> > As mentioned earlier, the whole helper function description below
> > should get a big cleanup in here when moved into libbpf API.
>
> Right, I just recalled that today, sorry I didn't do it for this version.
>
> There were two things you mentioned on that thread that you wanted to clean up:
> 1. using __u32 instead int and stuff like that
> 2. using macro to hide some of the ugliness of (void *) = BPF_FUNC_xxx
>
> So with 1) I'm concerned that we can't just assume that __u32 is
> always going to be defined. Also we need bpf_helpers.h to be usable
> both with including system headers, as well as auto-generated
> vmlinux.h. In first case, I don't think we can assume that typedef is
> always defined, in latter case we can't really define it on our own.
> So I think we should just keep it as int, unsigned long long, etc.
> Thoughts?
>
> For 2), I'm doing that right now, but it's not that much cleaner, let's see.
>
> Am I missing something else?
Ok, so this doesn't work with just
#define BPF_FUNC(NAME, ...) (*NAME)(__VA_ARGS__)
__attribute__((unused)) = (void *) BPF_FUNC_##NAME
because helper is called bpf_map_update_elem(), but enum value is
BPF_FUNC_map_update_elem (without bpf_ prefix). So one way to do this
would be to have bpf_ prepended to function name by macro:
static int BPF_FUNC(map_update_elem, ....);
But this is super confusing, because this definition becomes basically
un-greppable. I think we should just keep it as is, or go all the way
in for super-verbose
static int BPF_FUNC(BPF_FUNC_map_update_elem, bpf_map_elem, ...);
I hate both, honestly.
>
> >
> > > +static void *(*bpf_map_lookup_elem)(void *map, const void *key) =
> > > + (void *) BPF_FUNC_map_lookup_elem;
> > > +static int (*bpf_map_update_elem)(void *map, const void *key, const void *value,
> > > + unsigned long long flags) =
> > [...]
> > > +
[...]
> > > --
> > > 2.17.1
> > >
next prev parent reply other threads:[~2019-10-01 23:40 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-30 18:58 [PATCH bpf-next 0/6] Move bpf_helpers and add BPF_CORE_READ macros Andrii Nakryiko
2019-09-30 18:58 ` [PATCH bpf-next 1/6] selftests/bpf: undo GCC-specific bpf_helpers.h changes Andrii Nakryiko
2019-09-30 22:53 ` Song Liu
2019-10-01 10:25 ` Ilya Leoshkevich
2019-10-01 19:10 ` John Fastabend
2019-09-30 18:58 ` [PATCH bpf-next 2/6] libbpf: move bpf_helpers.h, bpf_endian.h into libbpf Andrii Nakryiko
2019-09-30 22:55 ` Song Liu
2019-09-30 22:58 ` Andrii Nakryiko
2019-09-30 23:18 ` Jakub Kicinski
2019-09-30 23:25 ` Song Liu
2019-09-30 23:36 ` Jakub Kicinski
2019-09-30 23:39 ` Song Liu
2019-09-30 23:30 ` Andrii Nakryiko
2019-09-30 23:43 ` Jakub Kicinski
2019-09-30 23:23 ` Song Liu
2019-09-30 23:27 ` Andrii Nakryiko
2019-09-30 23:35 ` Song Liu
2019-10-01 7:10 ` Toke Høiland-Jørgensen
2019-10-01 19:18 ` John Fastabend
2019-10-01 19:44 ` Andrii Nakryiko
2019-10-01 22:00 ` John Fastabend
2019-10-02 7:25 ` Toke Høiland-Jørgensen
2019-10-01 19:42 ` Andrii Nakryiko
2019-10-02 7:21 ` Toke Høiland-Jørgensen
2019-10-01 21:19 ` Song Liu
2019-10-01 21:28 ` Andrii Nakryiko
2019-10-01 22:45 ` Daniel Borkmann
2019-10-01 23:31 ` Andrii Nakryiko
2019-10-01 23:40 ` Andrii Nakryiko [this message]
2019-10-02 9:51 ` Daniel Borkmann
2019-09-30 18:58 ` [PATCH bpf-next 3/6] selftests/bpf: switch test to use libbpf's helpers Andrii Nakryiko
2019-09-30 18:58 ` [PATCH bpf-next 4/6] libbpf: add BPF_CORE_READ/BPF_CORE_READ_INTO helpers Andrii Nakryiko
2019-10-01 19:07 ` John Fastabend
2019-10-01 21:14 ` Song Liu
2019-10-01 21:25 ` Andrii Nakryiko
2019-10-01 21:46 ` Song Liu
2019-10-01 22:42 ` Andrii Nakryiko
2019-10-01 23:44 ` Song Liu
2019-10-02 3:36 ` Andrii Nakryiko
2019-10-02 16:25 ` Song Liu
2019-09-30 18:58 ` [PATCH bpf-next 5/6] selftests/bpf: adjust CO-RE reloc tests for new BPF_CORE_READ macro Andrii Nakryiko
2019-10-01 19:14 ` John Fastabend
2019-10-01 21:31 ` Andrii Nakryiko
2019-10-01 21:47 ` Song Liu
2019-09-30 18:58 ` [PATCH bpf-next 6/6] selftests/bpf: add BPF_CORE_READ and BPF_CORE_READ_STR_INTO macro tests Andrii Nakryiko
2019-10-01 19:19 ` John Fastabend
2019-10-01 21:22 ` Song Liu
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