diff --git a/configure b/configure
index 9ec19a5b..26e06eb8 100755
--- a/configure
+++ b/configure
@@ -485,12 +485,12 @@ usage()
 {
 	cat <<EOF
 Usage: $0 [OPTIONS]
-	--include_dir <dir>	Path to iproute2 include dir
-	--libbpf_dir <dir>	Path to libbpf DESTDIR
-	--libbpf_force		Enable/disable libbpf by force. Available options:
-				  on: require link against libbpf, quit config if no libbpf support
-				  off: disable libbpf probing
-	-h | --help		Show this usage info
+	--include_dir <dir>		Path to iproute2 include dir
+	--libbpf_dir <dir>		Path to libbpf DESTDIR
+	--libbpf_force <on|off>		Enable/disable libbpf by force. Available options:
+					  on: require link against libbpf, quit config if no libbpf support
+					  off: disable libbpf probing
+	-h | --help			Show this usage info
 EOF
 	exit $1
 }
@@ -499,31 +499,25 @@ EOF
 if [ $# -eq 1 ] && [ "$(echo $1 | cut -c 1)" != '-' ]; then
 	INCLUDE="$1"
 else
-	while true; do
+	while [ "$#" -gt 0 ]; do
 		case "$1" in
 			--include_dir)
 				shift
-				INCLUDE="$1"
-				[ "$#" -gt 0 ] && shift ;;
+				INCLUDE="$1" ;;
 			--libbpf_dir)
 				shift
-				LIBBPF_DIR="$1"
-				[ "$#" -gt 0 ] && shift ;;
+				LIBBPF_DIR="$1" ;;
 			--libbpf_force)
-				if [ "$2" != 'on' ] && [ "$2" != 'off' ]; then
-					usage 1
-				fi
-				LIBBPF_FORCE=$2
-				shift 2 ;;
+				shift
+				LIBBPF_FORCE="$1" ;;
 			-h | --help)
 				usage 0 ;;
 			--*)
-				shift ;;
-			"")
-				break ;;
+				;;
 			*)
 				usage 1 ;;
 		esac
+		[ "$#" -gt 0 ] && shift
 	done
 fi
 
@@ -531,6 +525,11 @@ fi
 if [ "${LIBBPF_DIR-unused}" != "unused" ]; then
 	[ -d "$LIBBPF_DIR" ] || usage 1
 fi
+if [ "${LIBBPF_FORCE-unused}" != "unused" ]; then
+	if [ "$LIBBPF_FORCE" != 'on' ] && [ "$LIBBPF_FORCE" != 'off' ]; then
+		usage 1
+	fi
+fi
 
 echo "# Generated config based on" $INCLUDE >$CONFIG
 quiet_config >> $CONFIG