-----Original Message----- From: Paolo Abeni pabeni@redhat.com Sent: Thursday, November 6, 2025 1:18 PM To: Chia-Yu Chang (Nokia) chia-yu.chang@nokia-bell-labs.com; edumazet@google.com; parav@nvidia.com; linux-doc@vger.kernel.org; corbet@lwn.net; horms@kernel.org; dsahern@kernel.org; kuniyu@google.com; bpf@vger.kernel.org; netdev@vger.kernel.org; dave.taht@gmail.com; jhs@mojatatu.com; kuba@kernel.org; stephen@networkplumber.org; xiyou.wangcong@gmail.com; jiri@resnulli.us; davem@davemloft.net; andrew+netdev@lunn.ch; donald.hunter@gmail.com; ast@fiberby.net; liuhangbin@gmail.com; shuah@kernel.org; linux-kselftest@vger.kernel.org; ij@kernel.org; ncardwell@google.com; Koen De Schepper (Nokia) koen.de_schepper@nokia-bell-labs.com; g.white@cablelabs.com; ingemar.s.johansson@ericsson.com; mirja.kuehlewind@ericsson.com; cheshire cheshire@apple.com; rs.ietf@gmx.at; Jason_Livingood@comcast.com; Vidhi Goel vidhi_goel@apple.com Subject: Re: [PATCH v5 net-next 11/14] tcp: accecn: unset ECT if receive or send ACE=0 in AccECN negotiaion
CAUTION: This is an external email. Please be very careful when clicking links or opening attachments. See the URL nok.it/ext for additional information.
On 10/30/25 3:34 PM, chia-yu.chang@nokia-bell-labs.com wrote:
@@ -4006,7 +4008,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, memset(th, 0, sizeof(struct tcphdr)); th->syn = 1; th->ack = 1;
tcp_ecn_make_synack(req, th);
tcp_ecn_make_synack((struct sock *)sk, req, th); th->source = htons(ireq->ir_num); th->dest = ireq->ir_rmt_port; skb->mark = ireq->ir_mark;Whoops, I missed the const cast in the previous revisions. This could make the code generated by the compiler for the caller incorrect - assuming the changed field is actually constant.
I don't have a good idea on how to address this. Changing the argument type for the whole call chain looks like a no go.
/P
One thought I have now is to add one extra flag in request_sock.
By using this new flag in rquest_sock after calling tcp_rtx_synack, the ACCECN_FAIL_MODE can be set in sk.
Would it make sense to you?
Chia-Yu