[PATCH 6.1.y 6/6] selftests: mptcp: join: fix local endp not being tracked

["Matthieu Baerts (NGI0)" <matttbe@kernel.org>]

commit c5d5ecf21fdd9ce91e6116feb3aa83cee73352cc upstream.

When running this mptcp_join.sh selftest on older kernel versions not
supporting local endpoints tracking, this test fails because 3 MP_JOIN
ACKs have been received, while only 2 were expected.

It is not clear why only 2 MP_JOIN ACKs were expected on old kernel
versions, while 3 MP_JOIN SYN and SYN+ACK were expected. When testing on
the v5.15.197 kernel, 3 MP_JOIN ACKs are seen, which is also what is
expected in the selftests included in this kernel version, see commit
f4480eaad489 ("selftests: mptcp: add missing join check").

Switch the expected MP_JOIN ACKs to 3. While at it, move this
chk_join_nr helper out of the special condition for older kernel
versions as it is now the same as with more recent ones. Also, invert
the condition to be more logical: what's expected on newer kernel
versions having such helper first.

Fixes: d4c81bbb8600 ("selftests: mptcp: join: support local endpoint being tracked or not")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20260127-net-mptcp-dup-nl-events-v1-5-7f71e1bc4feb@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ Conflicts in mptcp_join.sh, because commit e571fb09c893 ("selftests:
  mptcp: add speed env var") is not in this version, and caused
  conflicts in the context. The same modification can still be applied
  at the same place. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 7d4df90d6281..5a40e09e8374 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -2181,17 +2181,16 @@ signal_address_tests()
 		# the peer could possibly miss some addr notification, allow retransmission
 		ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=1
 		run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow
+		chk_join_nr 3 3 3
 
 		# It is not directly linked to the commit introducing this
 		# symbol but for the parent one which is linked anyway.
-		if ! mptcp_lib_kallsyms_has "mptcp_pm_subflow_check_next$"; then
-			chk_join_nr 3 3 2
-			chk_add_nr 4 4
-		else
-			chk_join_nr 3 3 3
+		if mptcp_lib_kallsyms_has "mptcp_pm_subflow_check_next$"; then
 			# the server will not signal the address terminating
 			# the MPC subflow
 			chk_add_nr 3 3
+		else
+			chk_add_nr 4 4
 		fi
 	fi
 }
-- 
2.51.0