From: bot+bpf-ci@kernel.org
To: kuniyu@google.com,ast@kernel.org,daniel@iogearbox.net,andrii@kernel.org,martin.lau@linux.dev,eddyz87@gmail.com,memxor@gmail.com
Cc: yonghong.song@linux.dev,john.fastabend@gmail.com,sdf@fomichev.me,edumazet@google.com,ncardwell@google.com,willemb@google.com,ukyab@berkeley.edu,cleger@meta.com,kuniyu@google.com,kuni1840@gmail.com,bpf@vger.kernel.org,netdev@vger.kernel.org,ast@kernel.org,andrii@kernel.org,daniel@iogearbox.net,martin.lau@kernel.org,eddyz87@gmail.com,yonghong.song@linux.dev,mason@kernel.org,ihor.solodrai@linux.dev
Subject: Re: [PATCH bpf-next 4/7] tcp: Split out __tcp_set_rcvlowat().
Date: Sun, 20 Sep 2026 21:01:17 +0000 (UTC) [thread overview]
Message-ID: <386c023dc4bca44689253b97a3f71c7758d9a320a014cb12e21562cba72a3443@mail.kernel.org> (raw)
In-Reply-To: <20260920195633.3033620-5-kuniyu@google.com>
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> In the enqueue path, tcp_data_ready() is always called after
> the hooks in tcp_queue_rcv() and tcp_ofo_queue().
Does this "always" claim hold for every enqueue-side hook site?
Looking at the callers of tcp_queue_rcv() in net/ipv4/tcp_input.c:
- tcp_data_queue() -> tcp_data_ready() at line 5709,
but only if (!sock_flag(sk, SOCK_DEAD))
- tcp_rcv_established() fast path -> tcp_data_ready() at line 6694
- tcp_send_rcvq() (line 5565, TCP repair, tp->repair_queue == TCP_RECV_QUEUE)
calls tcp_queue_rcv(sk, skb, &fragstolen) at line 5601 but never calls
tcp_data_ready() or sk->sk_data_ready() at all
And there's a third enqueue hook site the message doesn't mention:
bpf_tcp_ops_enqueue_rcvq() in tcp_fastopen_add_skb()
(net/ipv4/tcp_fastopen.c:284), which also has no following tcp_data_ready().
So wakeup == false doesn't always mean "a wakeup happens later" on the repair
and TFO paths. There's no functional regression since neither tcp_send_rcvq()
nor tcp_fastopen_add_skb() signalled the reader before this series either, and
the later commit 0390d95e0979c explains the tcp_fastopen_add_skb() case.
Could the changelog be more precise about which paths it covers? Perhaps naming
tcp_data_queue()/tcp_rcv_established() specifically, and noting that
tcp_send_rcvq()/tcp_fastopen_add_skb() have no reader to wake?
---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/35535082194
next prev parent reply other threads:[~2026-09-20 21:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-20 19:56 [PATCH bpf-next 0/7] bpf: Add bpf_tcp_ops hooks for TCP AutoLOWAT Kuniyuki Iwashima
2026-09-20 19:56 ` [PATCH bpf-next 1/7] selftest: bpf: Use BPF_SOCK_OPS_ALL_CB_FLAGS + 1 for bad_cb_test_rv Kuniyuki Iwashima
2026-09-21 20:48 ` Stanislav Fomichev
2026-09-20 19:56 ` [PATCH bpf-next 2/7] bpf: tcp: Introduce bpf_tcp_ops.{enqueue,dequeue}_rcvq() Kuniyuki Iwashima
2026-09-20 21:16 ` bot+bpf-ci
2026-09-21 20:48 ` Stanislav Fomichev
2026-09-20 19:56 ` [PATCH bpf-next 3/7] bpf: tcp: Support bpf_sock_ops_cb_flags_set() for bpf_tcp_ops Kuniyuki Iwashima
2026-09-21 20:48 ` Stanislav Fomichev
2026-09-20 19:56 ` [PATCH bpf-next 4/7] tcp: Split out __tcp_set_rcvlowat() Kuniyuki Iwashima
2026-09-20 21:01 ` bot+bpf-ci [this message]
2026-09-20 21:12 ` Kuniyuki Iwashima
2026-09-21 20:48 ` Stanislav Fomichev
2026-09-20 19:56 ` [PATCH bpf-next 5/7] bpf: mptcp: Don't support BPF_SOCK_OPS_RCVQ_CB_FLAG Kuniyuki Iwashima
2026-09-20 19:56 ` [PATCH bpf-next 6/7] bpf: tcp: Add kfunc to adjust sk->sk_rcvlowat Kuniyuki Iwashima
2026-09-20 21:16 ` bot+bpf-ci
2026-09-21 20:49 ` Stanislav Fomichev
2026-09-21 21:36 ` Kuniyuki Iwashima
2026-09-22 7:29 ` Clément Léger
2026-09-20 19:56 ` [PATCH bpf-next 7/7] selftest: bpf: Add test for bpf_tcp_ops.{enqueue,dequeue}_rcvq() Kuniyuki Iwashima
2026-09-20 21:16 ` bot+bpf-ci
2026-09-21 20:50 ` Stanislav Fomichev
2026-09-22 23:14 ` Kuniyuki Iwashima
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