From: Ilpo Järvinen Date: Sat, 31 Jan 2026 22:25:02 +0000 (+0100) Subject: gro: flushing when CWR is set negatively affects AccECN X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ab4c8b6f7fcbca7644487e08e76e4e224414bca5;p=thirdparty%2Fkernel%2Flinux.git gro: flushing when CWR is set negatively affects AccECN As AccECN may keep CWR bit asserted due to different interpretation of the bit, flushing with GRO because of CWR may effectively disable GRO until AccECN counter field changes such that CWR-bit becomes 0. There is no harm done from not immediately forwarding the CWR'ed segment with RFC3168 ECN. Signed-off-by: Ilpo Järvinen Signed-off-by: Chia-Yu Chang Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20260131222515.8485-3-chia-yu.chang@nokia-bell-labs.com Signed-off-by: Paolo Abeni --- diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c index 942a948f1a31..3b1fdcd3cb29 100644 --- a/net/ipv4/tcp_offload.c +++ b/net/ipv4/tcp_offload.c @@ -304,8 +304,7 @@ struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb, goto out_check_final; th2 = tcp_hdr(p); - flush = (__force int)(flags & TCP_FLAG_CWR); - flush |= (__force int)((flags ^ tcp_flag_word(th2)) & + flush = (__force int)((flags ^ tcp_flag_word(th2)) & ~(TCP_FLAG_FIN | TCP_FLAG_PSH)); flush |= (__force int)(th->ack_seq ^ th2->ack_seq); for (i = sizeof(*th); i < thlen; i += 4)