selftests: forwarding: ethtool_extended_state: Convert to busywait

Currently, this script sets up the test scenario, which is supposed to end
in an inability of the system to negotiate a link. It then waits for a bit,
and verifies that the system can diagnose why the link was not established.

The wait time for the scenario where different link speeds are forced on
the two ends of a loopback cable, was set to 4 seconds, which exactly
covered it. As of a recent mlxsw firmware update, this time gets longer,
and this test starts failing.

The time that selftests currently wait for links to be established is
currently $WAIT_TIMEOUT, or 20 seconds. It seems reasonable that if this is
the time necessary to establish and bring up a link, it should also be
enough to determine that a link cannot be established and why.

Therefore in this patch, convert the sleeps to busywaits, so that if a
failure is established sooner (as is expected), the test runs quicker. And
use $WAIT_TIMEOUT as the time to wait.

Signed-off-by: Petr Machata <[e-mail]>
Reviewed-by: Amit Cohen <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

tools/testing/selftests/net/forwarding/ethtool_extended_state.sh

···
 source lib.sh
 source ethtool_lib.sh
 
+TIMEOUT=$((WAIT_TIMEOUT * 1000)) # ms
+
 setup_prepare()
 {
 	swp1=${NETIFS[p1]}
···
 	swp3=$NETIF_NO_CABLE
 }
 
-ethtool_extended_state_check()
+ethtool_ext_state()
 {
 	local dev=$1; shift
 	local expected_ext_state=$1; shift
···
 		| sed -e 's/^[[:space:]]*//')
 	ext_state=$(echo $ext_state | cut -d "," -f1)
 
-	[[ $ext_state == $expected_ext_state ]]
-	check_err $? "Expected \"$expected_ext_state\", got \"$ext_state\""
-
-	[[ $ext_substate == $expected_ext_substate ]]
-	check_err $? "Expected \"$expected_ext_substate\", got \"$ext_substate\""
+	if [[ $ext_state != $expected_ext_state ]]; then
+		echo "Expected \"$expected_ext_state\", got \"$ext_state\""
+		return 1
+	fi
+	if [[ $ext_substate != $expected_ext_substate ]]; then
+		echo "Expected \"$expected_ext_substate\", got \"$ext_substate\""
+		return 1
+	fi
 }
 
 autoneg()
 {
+	local msg
+
 	RET=0
 
 	ip link set dev $swp1 up
 
-	sleep 4
-	ethtool_extended_state_check $swp1 "Autoneg" "No partner detected"
+	msg=$(busywait $TIMEOUT ethtool_ext_state $swp1 \
+			"Autoneg" "No partner detected")
+	check_err $? "$msg"
 
 	log_test "Autoneg, No partner detected"
 
···
 
 autoneg_force_mode()
 {
+	local msg
+
 	RET=0
 
 	ip link set dev $swp1 up
···
 	ethtool_set $swp1 speed $speed1 autoneg off
 	ethtool_set $swp2 speed $speed2 autoneg off
 
-	sleep 4
-	ethtool_extended_state_check $swp1 "Autoneg" \
-		"No partner detected during force mode"
+	msg=$(busywait $TIMEOUT ethtool_ext_state $swp1 \
+			"Autoneg" "No partner detected during force mode")
+	check_err $? "$msg"
 
-	ethtool_extended_state_check $swp2 "Autoneg" \
-		"No partner detected during force mode"
+	msg=$(busywait $TIMEOUT ethtool_ext_state $swp2 \
+			"Autoneg" "No partner detected during force mode")
+	check_err $? "$msg"
 
 	log_test "Autoneg, No partner detected during force mode"
 
···
 
 no_cable()
 {
+	local msg
+
 	RET=0
 
 	ip link set dev $swp3 up
 
-	sleep 1
-	ethtool_extended_state_check $swp3 "No cable"
+	msg=$(busywait $TIMEOUT ethtool_ext_state $swp3 "No cable")
+	check_err $? "$msg"
 
 	log_test "No cable"