All of lore.kernel.org
 help / color / mirror / Atom feed
From: Daniel Borkmann <daniel@iogearbox.net>
To: Martin KaFai Lau <martin.lau@linux.dev>
Cc: netdev@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
	Kui-Feng Lee <kuifeng@meta.com>,
	bpf@vger.kernel.org, ast@kernel.org, song@kernel.org,
	kernel-team@meta.com, andrii@kernel.org, sdf@google.com
Subject: Re: [PATCH bpf-next v7 2/8] net: Update an existing TCP congestion control algorithm.
Date: Fri, 17 Mar 2023 18:23:11 +0100	[thread overview]
Message-ID: <b8b54ef5-8a24-5886-8f4e-8856dbaa9c34@iogearbox.net> (raw)
In-Reply-To: <ee8cab13-9018-5f62-0415-16409ee1610b@linux.dev>

On 3/17/23 6:18 PM, Martin KaFai Lau wrote:
> On 3/17/23 8:23 AM, Daniel Borkmann wrote:
>>  From the function itself what is not clear whether
>> callers that replace an existing one should do the synchronize_rcu() themselves or if this should
>> be part of tcp_update_congestion_control?
> 
> bpf_struct_ops_map_free (in patch 1) also does synchronize_rcu() for another reason (bpf_setsockopt), so the caller (bpf_struct_ops) is doing it. From looking at tcp_unregister_congestion_control(), make sense that it is more correct to have another synchronize_rcu() also in tcp_update_congestion_control in case there will be other non bpf_struct_ops caller doing update in the future.

Agree, I was looking at 'bpf: Update the struct_ops of a bpf_link', and essentially as-is
it was implicit via map free. +1, tcp_update_congestion_control() would be more obvious and
better for other/non-BPF users.

Thanks,
Daniel

  reply	other threads:[~2023-03-17 17:23 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-16  2:36 [PATCH bpf-next v7 0/8] Transit between BPF TCP congestion controls Kui-Feng Lee
2023-03-16  2:36 ` [PATCH bpf-next v7 1/8] bpf: Retire the struct_ops map kvalue->refcnt Kui-Feng Lee
2023-03-17 16:47   ` Martin KaFai Lau
2023-03-17 20:41     ` Kui-Feng Lee
2023-03-16  2:36 ` [PATCH bpf-next v7 2/8] net: Update an existing TCP congestion control algorithm Kui-Feng Lee
2023-03-17 15:23   ` Daniel Borkmann
2023-03-17 17:18     ` Martin KaFai Lau
2023-03-17 17:23       ` Daniel Borkmann [this message]
2023-03-17 21:46         ` Kui-Feng Lee
2023-03-17 23:07     ` Kui-Feng Lee
2023-03-16  2:36 ` [PATCH bpf-next v7 3/8] bpf: Create links for BPF struct_ops maps Kui-Feng Lee
2023-03-17 18:10   ` Martin KaFai Lau
2023-03-17 20:52     ` Kui-Feng Lee
2023-03-16  2:36 ` [PATCH bpf-next v7 4/8] libbpf: Create a bpf_link in bpf_map__attach_struct_ops() Kui-Feng Lee
2023-03-17 18:44   ` Martin KaFai Lau
2023-03-17 21:00     ` Kui-Feng Lee
2023-03-17 22:23   ` Andrii Nakryiko
2023-03-17 23:48     ` Kui-Feng Lee
2023-03-16  2:36 ` [PATCH bpf-next v7 5/8] bpf: Update the struct_ops of a bpf_link Kui-Feng Lee
2023-03-17 19:23   ` Martin KaFai Lau
2023-03-17 21:39     ` Kui-Feng Lee
2023-03-18  1:11     ` Kui-Feng Lee
2023-03-18  5:38       ` Martin KaFai Lau
2023-03-17 22:27   ` Andrii Nakryiko
2023-03-18  0:41     ` Kui-Feng Lee
2023-03-16  2:36 ` [PATCH bpf-next v7 6/8] libbpf: Update a bpf_link with another struct_ops Kui-Feng Lee
2023-03-17 19:42   ` Martin KaFai Lau
2023-03-17 21:40     ` Kui-Feng Lee
2023-03-17 22:33   ` Andrii Nakryiko
2023-03-18  1:17     ` Kui-Feng Lee
2023-03-16  2:36 ` [PATCH bpf-next v7 7/8] libbpf: Use .struct_ops.link section to indicate a struct_ops with a link Kui-Feng Lee
2023-03-17 22:35   ` Andrii Nakryiko
2023-03-16  2:36 ` [PATCH bpf-next v7 8/8] selftests/bpf: Test switching TCP Congestion Control algorithms Kui-Feng Lee

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=b8b54ef5-8a24-5886-8f4e-8856dbaa9c34@iogearbox.net \
    --to=daniel@iogearbox.net \
    --cc=andrii@kernel.org \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=edumazet@google.com \
    --cc=kernel-team@meta.com \
    --cc=kuifeng@meta.com \
    --cc=martin.lau@linux.dev \
    --cc=netdev@vger.kernel.org \
    --cc=sdf@google.com \
    --cc=song@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.