selftests: forwarding: lib: Split out setup_wait_dev()

Split out of setup_wait() a function setup_wait_dev() that waits for a
single device. This gives tests the opportunity to wait for a selected
device after they tinkered with its upness.
Signed-off-by: NPetr Machata <petrm@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -185,18 +185,25 @@ log_info()
 	echo "INFO: $msg"
 }
 
+setup_wait_dev()
+{
+	local dev=$1; shift
+
+	while true; do
+		ip link show dev $dev up \
+			| grep 'state UP' &> /dev/null
+		if [[ $? -ne 0 ]]; then
+			sleep 1
+		else
+			break
+		fi
+	done
+}
+
 setup_wait()
 {
 	for i in $(eval echo {1..$NUM_NETIFS}); do
-		while true; do
-			ip link show dev ${NETIFS[p$i]} up \
-				| grep 'state UP' &> /dev/null
-			if [[ $? -ne 0 ]]; then
-				sleep 1
-			else
-				break
-			fi
-		done
+		setup_wait_dev ${NETIFS[p$i]}
 	done
 
 	# Make sure links are ready.