Merge branch 'selftests-net-introduce-deferred-commands'

Petr Machata says:

====================
selftests: net: Introduce deferred commands

Recently, a defer helper was added to Python selftests. The idea is to keep
cleanup commands close to their dirtying counterparts, thereby making it
more transparent what is cleaning up what, making it harder to miss a
cleanup, and make the whole cleanup business exception safe. All these
benefits are applicable to bash as well, exception safety can be
interpreted in terms of safety vs. a SIGINT.

This patchset therefore introduces a framework of several helpers that
serve to schedule cleanups in bash selftests.

- Patch #1 has more details about the primitives being introduced.
  Patch #2 adds a fallback cleanup() function to lib.sh, because ideally
  selftests wouldn't need to introduce a dedicated cleanup function at all.

- Patch #3 adds a parameter to stop_traffic(), which makes it possible to
  start other background processes after the traffic is started without
  confusing the cleanup.

- Patches #4 to #10 convert a number of selftests.

  The goal was to convert all tests that use start_traffic / stop_traffic
  to the defer framework. Leftover traffic generators are a particularly
  painful sort of a missed cleanup. Normal unfinished cleanups can usually
  be cleaned up simply by rerunning the test and interrupting it early to
  let the cleanups run again / in full. This does not work with
  stop_traffic, because it is only issued at the end of the test case that
  starts the traffic. At the same time, leftover traffic generators
  influence follow-up test runs, and are hard to notice.

  The tests were however converted whole-sale, not just their traffic bits.
  Thus they form a proof of concept of the defer framework.
====================

Link: https://patch.msgid.link/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

Author: Paolo Abeni

tools/testing/selftests/drivers/net/mlxsw/devlink_trap_policer.sh

@@ -45,63 +45,52 @@ source $lib_dir/devlink_lib.sh
 h1_create()
 {
 	simple_if_init $h1 192.0.2.1/24
+	defer simple_if_fini $h1 192.0.2.1/24
+
 	mtu_set $h1 10000
+	defer mtu_restore $h1
 
 	ip -4 route add default vrf v$h1 nexthop via 192.0.2.2
-}
-
-h1_destroy()
-{
-	ip -4 route del default vrf v$h1 nexthop via 192.0.2.2
-
-	mtu_restore $h1
-	simple_if_fini $h1 192.0.2.1/24
+	defer ip -4 route del default vrf v$h1 nexthop via 192.0.2.2
 }
 
 h2_create()
 {
 	simple_if_init $h2 198.51.100.1/24
+	defer simple_if_fini $h2 198.51.100.1/24
+
 	mtu_set $h2 10000
+	defer mtu_restore $h2
 
 	ip -4 route add default vrf v$h2 nexthop via 198.51.100.2
-}
-
-h2_destroy()
-{
-	ip -4 route del default vrf v$h2 nexthop via 198.51.100.2
-
-	mtu_restore $h2
-	simple_if_fini $h2 198.51.100.1/24
+	defer ip -4 route del default vrf v$h2 nexthop via 198.51.100.2
 }
 
 router_create()
 {
 	ip link set dev $rp1 up
+	defer ip link set dev $rp1 down
+
 	ip link set dev $rp2 up
+	defer ip link set dev $rp2 down
 
 	__addr_add_del $rp1 add 192.0.2.2/24
+	defer __addr_add_del $rp1 del 192.0.2.2/24
+
 	__addr_add_del $rp2 add 198.51.100.2/24
+	defer __addr_add_del $rp2 del 198.51.100.2/24
+
 	mtu_set $rp1 10000
+	defer mtu_restore $rp1
+
 	mtu_set $rp2 10000
+	defer mtu_restore $rp2
 
 	ip -4 route add blackhole 198.51.100.100
+	defer ip -4 route del blackhole 198.51.100.100
 
 	devlink trap set $DEVLINK_DEV trap blackhole_route action trap
-}
-
-router_destroy()
-{
-	devlink trap set $DEVLINK_DEV trap blackhole_route action drop
-
-	ip -4 route del blackhole 198.51.100.100
-
-	mtu_restore $rp2
-	mtu_restore $rp1
-	__addr_add_del $rp2 del 198.51.100.2/24
-	__addr_add_del $rp1 del 192.0.2.2/24
-
-	ip link set dev $rp2 down
-	ip link set dev $rp1 down
+	defer devlink trap set $DEVLINK_DEV trap blackhole_route action drop
 }
 
 setup_prepare()
@@ -114,29 +103,18 @@ setup_prepare()
 
 	rp1_mac=$(mac_get $rp1)
 
+	# Reload to ensure devlink-trap settings are back to default.
+	defer devlink_reload
+
 	vrf_prepare
+	defer vrf_cleanup
 
 	h1_create
 	h2_create
 
 	router_create
 }
 
-cleanup()
-{
-	pre_cleanup
-
-	router_destroy
-
-	h2_destroy
-	h1_destroy
-
-	vrf_cleanup
-
-	# Reload to ensure devlink-trap settings are back to default.
-	devlink_reload
-}
-
 rate_limits_test()
 {
 	RET=0
@@ -214,7 +192,10 @@ __rate_test()
 	# by the policer. Make sure measured received rate is about 1000 pps
 	log_info "=== Tx rate: Highest, Policer rate: 1000 pps ==="
 
+	defer_scope_push
+
 	start_traffic $h1 192.0.2.1 198.51.100.100 $rp1_mac
+	defer stop_traffic $!
 
 	sleep 5 # Take measurements when rate is stable
 
@@ -229,13 +210,16 @@ __rate_test()
 	check_err $? "Expected non-zero policer drop rate, got 0"
 	log_info "Measured policer drop rate of $drop_rate pps"
 
-	stop_traffic
+	defer_scope_pop
 
 	# Send packets at a rate of 1000 pps and make sure they are not dropped
 	# by the policer
 	log_info "=== Tx rate: 1000 pps, Policer rate: 1000 pps ==="
 
+	defer_scope_push
+
 	start_traffic $h1 192.0.2.1 198.51.100.100 $rp1_mac -d 1msec
+	defer stop_traffic $!
 
 	sleep 5 # Take measurements when rate is stable
 
@@ -244,7 +228,7 @@ __rate_test()
 	check_err $? "Expected zero policer drop rate, got a drop rate of $drop_rate pps"
 	log_info "Measured policer drop rate of $drop_rate pps"
 
-	stop_traffic
+	defer_scope_pop
 
 	# Unbind the policer and send packets at highest possible rate. Make
 	# sure they are not dropped by the policer and that the measured
@@ -253,7 +237,10 @@ __rate_test()
 
 	devlink trap group set $DEVLINK_DEV group l3_drops nopolicer
 
+	defer_scope_push
+
 	start_traffic $h1 192.0.2.1 198.51.100.100 $rp1_mac
+	defer stop_traffic $!
 
 	rate=$(trap_rate_get)
 	(( rate > 1000 ))
@@ -265,7 +252,7 @@ __rate_test()
 	check_err $? "Expected zero policer drop rate, got a drop rate of $drop_rate pps"
 	log_info "Measured policer drop rate of $drop_rate pps"
 
-	stop_traffic
+	defer_scope_pop
 
 	log_test "Trap policer rate"
 }