> -----Original Message-----
> From: Neal Cardwell <[email protected]>
> Sent: Monday, October 19, 2026 5:31 PM
> To: Chia-Yu Chang (Nokia) <[email protected]>
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> Subject: Re: [PATCH net-next v2 2/3] tcp: ECT_1_ESTABLISH identifier for CA
>
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> On Sun, Oct 18, 2026 at 5:15 PM <[email protected]> wrote:
> >
> > From: Chia-Yu Chang <[email protected]>
> >
> > When connection is initialized after ECN negotiation, this patch
> > enables CA to control whether ECT(0) or ECT(1) should be used.
>
> AFAICT this should be "When congestion control is initialized" rather than
> 'When connection is initialized".
>
> > A new identiifer (TCP_CONG_ECT_1_ESTABLISH) defines the expected ECT
> > value in the IP header.
>
> Using "expected" here is not as clear as it could be. It sounds like the
> expected incoming value rather than a value that the CC algorithm is
> specifying should be sent.
>
> Also, the name TCP_CONG_ECT_1_ESTABLISH is quite verbose, and not 100%
> accurate AFAICT, since it is used in tcp_ecn_send(), which is called when the
> SYN bit is not set, which can be in a number of TCP states other than
> ESTABLISHED.
>
> I would suggest calling this something shorter and more clear and correct,
> like TCP_ECN_SEND_ECT_1.
>
> Putting that all together, how about something like:
>
> """
> This patch introduces the new TCP_ECN_SEND_ECT_1 bit, which enables a
> congestion control module to control whether the connection transmits using
> ECT(1) (if the bit is set) or ECT(0) (otherwise), when congestion control is
> initialized after ECN negotiation. A congestion control module, such as the
> upcoming TCP Prague using L4S ECN, can set this new TCP_ECN_SEND_ECT_1 bit
> if it wants to send the ECT(1) code point in outgoing IP headers.
> """
>
You are right, I will modiy the commit message in the next version.
[...]
> > diff --git a/include/net/tcp_ecn.h b/include/net/tcp_ecn.h index
> > 865d5c5a7718..210ec63538f8 100644
> > --- a/include/net/tcp_ecn.h
> > +++ b/include/net/tcp_ecn.h
> > @@ -38,6 +38,12 @@ static inline void
> > INET_ECN_xmit_ect_1_negotiation(struct sock *sk)
> > __INET_ECN_xmit(sk, tcp_ca_ect_1_negotiation(sk)); }
> >
> > +/* Apply either ECT(0) or ECT(1) based on TCP_CONG_ECT_1_ESTABLISH
> > +flag */ static inline void INET_ECN_xmit_ect_1_establish(struct sock
> > +*sk) {
> > + __INET_ECN_xmit(sk, tcp_sk(sk)->ecn_flags &
> > +TCP_ECN_ECT_1_ESTABLISH); }
>
> This function name is quite verbose, and a little confusing, since it may or
> may not set the ECT code point to ECT(1). I realize the name is chosen to be
> consistent with INET_ECN_xmit_ect_1_negotiation(). But that one is confusing
> in the same way. :-)
>
> Also, using "establish" in this way sounds like a verb, making it sound like
> this function is establishing something.
>
> How about something like:
>
> (1) a new preceding patch in the series can rename
> INET_ECN_xmit_ect_1_negotiation() to INET_ECN_xmit_negotiation_ect()
> (2) this patch can rename its INET_ECN_xmit_ect_1_establish to
> INET_ECN_xmit_established_ect()
>
> Thanks for the patch!
>
> neal
Yes, I will add another patch to rename ECN transmit helper function from
"INET_ECN_xmit_ect_1_negotiation" to "INET_ECN_xmit_negotiation_ect"
Thanks!
Chia-Yu
