commit 689f7ff6169e57d37eea9f24c1065195e9c1e110
Author: Mark Johnston <markj@FreeBSD.org>
Date:   Sat Jun 17 12:02:52 2023 -0400

    Revert "icmp6: Hack to handle unmapped mbufs"
    
    This reverts commit c142b0f2741ef779ca8bd1a812d610ae1788b46b.

diff --git a/sys/netinet6/icmp6.c b/sys/netinet6/icmp6.c
index 83054a3f81eb..4166cabdc5cb 100644
--- a/sys/netinet6/icmp6.c
+++ b/sys/netinet6/icmp6.c
@@ -2126,10 +2126,6 @@ icmp6_reflect(struct mbuf *m, size_t off)
 	ip6->ip6_nxt = IPPROTO_ICMPV6;
 	ip6->ip6_hlim = hlim;
 
-	/* XXX-MJ in6_cksum() does not yet handle unmapped mbufs */
-	m = mb_unmapped_to_ext(m);
-	if (m == NULL)
-		goto bad;
 	icmp6->icmp6_cksum = 0;
 	icmp6->icmp6_cksum = in6_cksum(m, IPPROTO_ICMPV6,
 	    sizeof(struct ip6_hdr), plen);
@@ -2625,10 +2621,6 @@ noredhdropt:;
 
 	ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 
-	/* XXX-MJ in6_cksum() does not yet handle unmapped mbufs */
-	m = mb_unmapped_to_ext(m);
-	if (m == NULL)
-		goto fail;
 	nd_rd->nd_rd_cksum = 0;
 	nd_rd->nd_rd_cksum = in6_cksum(m, IPPROTO_ICMPV6,
 	    sizeof(*ip6), ntohs(ip6->ip6_plen));