From: Jan Klemkow <jan@openbsd.org>
Subject: SoftLRO: remove 8 segment limit
To: tech@openbsd.org
Date: Thu, 14 Aug 2025 20:42:36 +0200

Hi,

The limit of 8 segments is no longer needed after the last fix[1].
Thus, this code can be removed.

ok?

bye,
Jan

[1]: https://cvsweb.openbsd.org/src/sys/netinet/tcp_input.c?rev=1.458&content-type=text/x-cvsweb-markup

Index: netinet/tcp_input.c
===================================================================
RCS file: /cvs/src/sys/netinet/tcp_input.c,v
diff -u -p -r1.460 tcp_input.c
--- netinet/tcp_input.c	14 Aug 2025 08:50:25 -0000	1.460
+++ netinet/tcp_input.c	14 Aug 2025 18:33:59 -0000
@@ -4500,8 +4500,7 @@ void
 tcp_softlro_glue(struct mbuf_list *ml, struct mbuf *mtail, struct ifnet *ifp)
 {
 	struct ether_extracted head, tail;
-	struct mbuf *m, *mhead;
-	unsigned int headcnt, tailcnt;
+	struct mbuf *mhead;
 
 	if (!ISSET(ifp->if_xflags, IFXF_LRO))
 		goto dontmerge;
@@ -4524,12 +4523,6 @@ tcp_softlro_glue(struct mbuf_list *ml, s
 	if (!tcp_softlro_check(mtail, &tail))
 		goto dontmerge;
 
-	tailcnt = 0;
-	for (m = mtail; m != NULL; m = m->m_next) {
-		if (tailcnt++ >= 8)
-			goto dontmerge;
-	}
-
 	mtail->m_pkthdr.ph_mss = tail.paylen;
 
 	for (mhead = ml->ml_head; mhead != NULL; mhead = mhead->m_nextpkt) {
@@ -4563,13 +4556,6 @@ tcp_softlro_glue(struct mbuf_list *ml, s
 		ether_extract_headers(mhead, &head);
 		if (!tcp_softlro_compare(&head, &tail))
 			continue;
-
-		/* Limit mbuf chain to avoid m_defrag calls when forwarding. */
-		headcnt = tailcnt;
-		for (m = mhead; m != NULL; m = m->m_next) {
-			if (headcnt++ >= 8)
-				goto dontmerge;
-		}
 
 		tcp_softlro_concat(mhead, &head, mtail, &tail);
 		return;