From: "Toke Høiland-Jørgensen" <toke@redhat.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
Jiri Olsa <jolsa@redhat.com>,
Eelco Chaudron <echaudro@redhat.com>,
KP Singh <kpsingh@chromium.org>,
Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next v5 4/8] bpf: support attaching freplace programs to multiple attach points
Date: Wed, 16 Sep 2020 23:13:18 +0200 [thread overview]
Message-ID: <87r1r1pgr5.fsf@toke.dk> (raw)
In-Reply-To: <CAEf4BzYP6MpVEqJ1TVW6rcfqJjkBi9x9U9F8MZPQdGMmoaUX_A@mail.gmail.com>
[ will fix all your comments above ]
>> @@ -3924,10 +3983,16 @@ static int tracing_bpf_link_attach(const union bpf_attr *attr, struct bpf_prog *
>> prog->expected_attach_type == BPF_TRACE_ITER)
>> return bpf_iter_link_attach(attr, prog);
>>
>> + if (attr->link_create.attach_type == BPF_TRACE_FREPLACE &&
>> + !prog->expected_attach_type)
>> + return bpf_tracing_prog_attach(prog,
>> + attr->link_create.target_fd,
>> + attr->link_create.target_btf_id);
>
> Hm.. so you added a "fake" BPF_TRACE_FREPLACE attach_type, which is
> not really set with BPF_PROG_TYPE_EXT and is only specified for the
> LINK_CREATE command. Are you just trying to satisfy the link_create
> flow of going from attach_type to program type? If that's the only
> reason, I think we can adjust link_create code to handle this more
> flexibly.
>
> I need to think a bit more whether we want BPF_TRACE_FREPLACE at all,
> but if we do, whether we should make it an expected_attach_type for
> BPF_PROG_TYPE_EXT then...
Yeah, wasn't too sure about this. But attach_type seemed to be the only
way to disambiguate between the different link types in the LINK_CREATE
command, so went with that. Didn't think too much about it, TBH :)
I guess an alternative could be to just enforce attach_type==0 and look
at prog->type? Or if you have any other ideas, I'm all ears!
-Toke
next prev parent reply other threads:[~2020-09-16 22:14 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-15 11:40 [PATCH bpf-next v5 0/8] bpf: Support multi-attach for freplace programs Toke Høiland-Jørgensen
2020-09-15 11:40 ` [PATCH bpf-next v5 1/8] bpf: change logging calls from verbose() to bpf_log() and use log pointer Toke Høiland-Jørgensen
2020-09-16 17:08 ` Andrii Nakryiko
2020-09-15 11:40 ` [PATCH bpf-next v5 2/8] bpf: verifier: refactor check_attach_btf_id() Toke Høiland-Jørgensen
2020-09-16 17:32 ` Andrii Nakryiko
2020-09-16 21:07 ` Toke Høiland-Jørgensen
2020-09-17 10:06 ` Toke Høiland-Jørgensen
2020-09-17 16:38 ` Andrii Nakryiko
2020-09-17 16:54 ` Toke Høiland-Jørgensen
2020-09-15 11:41 ` [PATCH bpf-next v5 3/8] bpf: move prog->aux->linked_prog and trampoline into bpf_link on attach Toke Høiland-Jørgensen
2020-09-16 18:22 ` Andrii Nakryiko
2020-09-15 11:41 ` [PATCH bpf-next v5 4/8] bpf: support attaching freplace programs to multiple attach points Toke Høiland-Jørgensen
2020-09-16 19:49 ` Andrii Nakryiko
2020-09-16 21:13 ` Toke Høiland-Jørgensen [this message]
2020-09-16 21:17 ` Andrii Nakryiko
2020-09-16 21:27 ` Toke Høiland-Jørgensen
2020-09-15 11:41 ` [PATCH bpf-next v5 5/8] bpf: Fix context type resolving for extension programs Toke Høiland-Jørgensen
2020-09-16 19:59 ` Andrii Nakryiko
2020-09-16 20:28 ` Andrii Nakryiko
2020-09-16 21:15 ` Toke Høiland-Jørgensen
2020-09-17 17:10 ` Toke Høiland-Jørgensen
2020-09-17 18:06 ` Andrii Nakryiko
2020-09-17 18:44 ` Toke Høiland-Jørgensen
2020-09-15 11:41 ` [PATCH bpf-next v5 6/8] libbpf: add support for freplace attachment in bpf_link_create Toke Høiland-Jørgensen
2020-09-16 20:37 ` Andrii Nakryiko
2020-09-16 20:45 ` Andrii Nakryiko
2020-09-16 21:21 ` Toke Høiland-Jørgensen
2020-09-16 21:24 ` Andrii Nakryiko
2020-09-16 21:41 ` Toke Høiland-Jørgensen
2020-09-15 11:41 ` [PATCH bpf-next v5 7/8] selftests: add test for multiple attachments of freplace program Toke Høiland-Jørgensen
2020-09-15 11:41 ` [PATCH bpf-next v5 8/8] selftests/bpf: Adding test for arg dereference in extension trace Toke Høiland-Jørgensen
2020-09-16 20:44 ` Andrii Nakryiko
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