[PATCH 6.6.y] selftests: mptcp: join: stop transfer when check is done (part 1)

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

Since the "Fixes" commit mentioned below, "userspace pm" subtests of
mptcp_join selftests introduced in v6.5 are launching the whole transfer
in the background, do the required checks, then wait for the end of
transfer.

There is no need to wait longer, especially because the checks at the
end of the transfer are ignored (which is fine). This saves quite a few
seconds in slow environments.

Note that old versions will need commit bdbef0a6ff10 ("selftests: mptcp:
add mptcp_lib_kill_wait") as well to get 'mptcp_lib_kill_wait()' helper.

Fixes: 4369c198e599 ("selftests: mptcp: test userspace pm out of transfer")
Cc: stable@vger.kernel.org # 6.5.x: bdbef0a6ff10: selftests: mptcp: add mptcp_lib_kill_wait
Cc: stable@vger.kernel.org # 6.5.x
Reviewed-and-tested-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240131-upstream-net-20240131-mptcp-ci-issues-v1-8-4c1c11e571ff@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(cherry picked from commit 31ee4ad86afd6ed6f4bb1b38c43011216080c42a)
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Notes:
 - conflicts because "userspace pm create id 0 subflow" test is not in
   v6.6.x
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 67ca22856d54..a0584417bcab 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -3430,7 +3430,7 @@ userspace_tests()
 		chk_rm_nr 1 1 invert
 		chk_mptcp_info subflows 0 subflows 0
 		kill_events_pids
-		wait $tests_pid
+		mptcp_lib_kill_wait $tests_pid
 	fi
 
 	# userspace pm create destroy subflow
@@ -3449,7 +3449,7 @@ userspace_tests()
 		chk_rm_nr 1 1
 		chk_mptcp_info subflows 0 subflows 0
 		kill_events_pids
-		wait $tests_pid
+		mptcp_lib_kill_wait $tests_pid
 	fi
 }
 
-- 
2.43.0