Re: [PATCH v12 net-next 12/15] tcp: accecn: AccECN option send control

On 7/15/25 5:14 PM, Chia-Yu Chang (Nokia) wrote:

...

On 7/4/25 10:53 AM, chia-yu.chang@nokia-bell-labs.com wrote:

...

@@ -285,9 +297,33 @@ static inline void tcp_ecn_received_counters(struct sock *sk,

          if (len > 0) {
                  u8 minlen = 

tcp_ecnfield_to_accecn_optfield(ecnfield);

•                 u32 oldbytes = tp->received_ecn_bytes[ecnfield - 
  

• 1];

•                 tp->received_ecn_bytes[ecnfield - 1] += len;
                  tp->accecn_minlen = max_t(u8, tp->accecn_minlen,
                                            minlen);
  

•                 /* Demand AccECN option at least every 2^22 bytes to
  

•                  * avoid overflowing the ECN byte counters.
  

•                  */
  

•                 if ((tp->received_ecn_bytes[ecnfield - 1] ^ oldbytes) &
  

•                     ~((1 << 22) - 1)) {
  

I don't understand the above statement, I don't think it yield the result expected according to the above comment.

Hi Paolo,

I was thinking to change it into GENMASK_U32() and comments like below.

It is intended to send AccECN option at least once per 2^22-byte increase in the counter.

Ok, I see it now. Please mention explicitly the above in the comment and test just the 22 bit.

/P