diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index cb5fd24..dd08944 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -312,7 +312,15 @@
 my @highlights = @highlights_man;
 my $blankline = $blankline_man;
 my $modulename = "Kernel API";
-my $function_only = 0;
+
+use constant {
+    OUTPUT_ALL          => 0, # output all symbols and doc sections
+    OUTPUT_INCLUDE      => 1, # output only specified symbols
+    OUTPUT_EXCLUDE      => 2, # output everything except specified symbols
+    OUTPUT_EXPORTED     => 3, # output exported symbols
+    OUTPUT_INTERNAL     => 4, # output non-exported symbols
+};
+my $output_selection = OUTPUT_ALL;
 my $show_not_found = 0;
 
 my @build_time;
@@ -449,18 +457,18 @@
     } elsif ($cmd eq "-module") { # not needed for XML, inherits from calling document
 	$modulename = shift @ARGV;
     } elsif ($cmd eq "-function") { # to only output specific functions
-	$function_only = 1;
+	$output_selection = OUTPUT_INCLUDE;
 	$function = shift @ARGV;
 	$function_table{$function} = 1;
-    } elsif ($cmd eq "-nofunction") { # to only output specific functions
-	$function_only = 2;
+    } elsif ($cmd eq "-nofunction") { # output all except specific functions
+	$output_selection = OUTPUT_EXCLUDE;
 	$function = shift @ARGV;
 	$function_table{$function} = 1;
     } elsif ($cmd eq "-export") { # only exported symbols
-	$function_only = 3;
+	$output_selection = OUTPUT_EXPORTED;
 	%function_table = ()
     } elsif ($cmd eq "-internal") { # only non-exported symbols
-	$function_only = 4;
+	$output_selection = OUTPUT_INTERNAL;
 	%function_table = ()
     } elsif ($cmd eq "-v") {
 	$verbose = 1;
@@ -530,15 +538,17 @@
         return;
     }
 
-    if (($function_only == 0) ||
-	( $function_only == 1 && defined($function_table{$name})) ||
-	( $function_only == 2 && !defined($function_table{$name})))
+    if (($output_selection == OUTPUT_ALL) ||
+	($output_selection == OUTPUT_INCLUDE &&
+	 defined($function_table{$name})) ||
+	($output_selection == OUTPUT_EXCLUDE &&
+	 !defined($function_table{$name})))
     {
 	dump_section($file, $name, $contents);
 	output_blockhead({'sectionlist' => \@sectionlist,
 			  'sections' => \%sections,
 			  'module' => $modulename,
-			  'content-only' => ($function_only != 0), });
+			  'content-only' => ($output_selection != OUTPUT_ALL), });
     }
 }
 
@@ -1988,11 +1998,13 @@
     my $name = shift;
     my $functype = shift;
     my $func = "output_${functype}_$output_mode";
-    if (($function_only==0) ||
-	( ($function_only == 1 || $function_only == 3) &&
-	  defined($function_table{$name})) ||
-	( ($function_only == 2 || $function_only == 4) &&
-	  !($functype eq "function" && defined($function_table{$name}))))
+    if (($output_selection == OUTPUT_ALL) ||
+	(($output_selection == OUTPUT_INCLUDE ||
+	  $output_selection == OUTPUT_EXPORTED) &&
+	 defined($function_table{$name})) ||
+	(($output_selection == OUTPUT_EXCLUDE ||
+	  $output_selection == OUTPUT_INTERNAL) &&
+	 !($functype eq "function" && defined($function_table{$name}))))
     {
 	&$func(@_);
 	$section_counter++;
@@ -2696,7 +2708,8 @@
     }
 
     # two passes for -export and -internal
-    if ($function_only == 3 || $function_only == 4) {
+    if ($output_selection == OUTPUT_EXPORTED ||
+	$output_selection == OUTPUT_INTERNAL) {
 	while (<IN>) {
 	    if (/$export_symbol/o) {
 		$function_table{$2} = 1;
@@ -2929,7 +2942,7 @@
     }
     if ($initial_section_counter == $section_counter) {
 	print STDERR "${file}:1: warning: no structured comments found\n";
-	if (($function_only == 1) && ($show_not_found == 1)) {
+	if (($output_selection == OUTPUT_INCLUDE) && ($show_not_found == 1)) {
 	    print STDERR "    Was looking for '$_'.\n" for keys %function_table;
 	}
 	if ($output_mode eq "xml") {