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smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eG2tuZkS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eG2tuZkS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8CECCC4CED3; Mon, 23 Dec 2024 09:49:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734947352; bh=ILoBGbWdjkiAvwVl8EVvqaF2c+2IjBCsIzeUWpLnPJo=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=eG2tuZkS8AA2YSlTthIoIL7mNpd0kzTpbsFD6LOHzUSbUl6J/3+yJ7pz/ZYMB/1Eo R+AIMjTfkEfCVM6LUocjG79W8u+ec60kzsAI99eBKrWGf6q3IvL7o6XvvvFV9xqlMw wTUMmOvHaxF4nGUoOtubWMCVtt7aB0eE/IF799T7mfpkZ10LrSWtH1ecMrV7+tFtiK Bl4nHvADY9KQdi+T6hfjKJO5xBbrUuB0hYdDtQIF2nj/1jJduOZtC1OucjcZFpQj42 opjq8tmmrG8i5I66wjTITY9szsFPJ2T5OfwlmblCer1pHpCI0sPrwDp/nSyNB/rupG rAz1qEaILueRA== Message-ID: <2e5968e1c5b213b633c1c844269d1c55c2a43ffb.camel@kernel.org> Subject: Re: [PATCH mptcp-next 2/8] Squash to "selftests/bpf: Add bpf_first scheduler & test" From: Geliang Tang To: Mat Martineau Cc: mptcp@lists.linux.dev, baohua@kernel.org, Geliang Tang Date: Mon, 23 Dec 2024 17:49:09 +0800 In-Reply-To: References: Autocrypt: addr=geliang@kernel.org; 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charset="UTF-8" User-Agent: Evolution 3.54.0-1 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Mat, Thanks for your review. On Fri, 2024-12-20 at 17:28 -0800, Mat Martineau wrote: > On Thu, 21 Nov 2024, Geliang Tang wrote: > > > From: Geliang Tang > > > > Split get_subflow() interface into two: get_send() and > > get_retrans(). > > > > Signed-off-by: Geliang Tang > > --- > > .../selftests/bpf/progs/mptcp_bpf_first.c     | 24 +++++++++++++++- > > --- > > 1 file changed, 19 insertions(+), 5 deletions(-) > > > > diff --git a/tools/testing/selftests/bpf/progs/mptcp_bpf_first.c > > b/tools/testing/selftests/bpf/progs/mptcp_bpf_first.c > > index d57399b407a7..36bf9adffb2c 100644 > > --- a/tools/testing/selftests/bpf/progs/mptcp_bpf_first.c > > +++ b/tools/testing/selftests/bpf/progs/mptcp_bpf_first.c > > @@ -16,18 +16,32 @@ void BPF_PROG(mptcp_sched_first_release, struct > > mptcp_sock *msk) > > { > > } > > > > -SEC("struct_ops") > > -int BPF_PROG(bpf_first_get_subflow, struct mptcp_sock *msk, > > -      struct mptcp_sched_data *data) > > +static int bpf_first_get_subflow(struct mptcp_sock *msk, > > + struct mptcp_sched_data *data) > > { > > mptcp_subflow_set_scheduled(bpf_mptcp_subflow_ctx_by_pos(d > > ata, 0), true); > > return 0; > > } > > > > -SEC(".struct_ops") > > +SEC("struct_ops") > > +int BPF_PROG(bpf_first_get_send, struct mptcp_sock *msk, > > +      struct mptcp_sched_data *data) > > +{ > > + return bpf_first_get_subflow(msk, data); > > +} > > + > > +SEC("struct_ops") > > +int BPF_PROG(bpf_first_get_retrans, struct mptcp_sock *msk, > > +      struct mptcp_sched_data *data) > > +{ > > + return bpf_first_get_subflow(msk, data); > > +} > > Hi Geliang - > > If my suggestion in patch 1 (use get_send for retransmit scheduling > if > get_retrans is NULL) doesn't seem like clear enough behavior for BPF The suggestion in patch 1 works well, I updated it in v2. > > scheduler authors, this code and the following patches could be > simplified > by removing the duplicate _retrans function above... > > > + > > +SEC(".struct_ops.link") > > struct mptcp_sched_ops first = { > > .init = (void *)mptcp_sched_first_init, > > .release = (void *)mptcp_sched_first_release, > > - .get_subflow = (void *)bpf_first_get_subflow, > > + .get_send = (void *)bpf_first_get_send, > > + .get_retrans = (void *)bpf_first_get_retrans, > > ... and setting get_retrans like this: >   .get_retrans = (void *)bpf_first_get_send, If we do this, libbpf will report the following error: # libbpf: struct_ops init_kern first func ptr get_retrans: invalid reuse of prog bpf_first_get_send in sec struct_ops with type 27: expected_attach_type 0 != kern_member_idx 1 # libbpf: failed to load object 'mptcp_bpf_first' # libbpf: failed to load BPF skeleton 'mptcp_bpf_first': -EINVAL # test_first:FAIL:open_and_load: first unexpected error: -22 So in v2, I didn't set this get_retrans ptr, but let it be NULL. Thanks, -Geliang > > Then there would be example code for BPF scheduler programmers to see > that > it's ok to use the same function pointer in both fields. > > - Mat > > > .name = "bpf_first", > > }; > > -- > > 2.43.0 > > > > > >