headers_check: recursively search for linux/types.h inclusion

headers_check.pl currently emits some spurious warnings, especially for
the drm headers, about using __[us]{8,16,32,64} types without including
linux/types.h.  Recursively search for types.h inclusion, avoiding
circular references.

Signed-off-by: Bobby Powers <bobbypowers@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>

Author: bpowers

scripts/headers_check.pl

@@ -19,6 +19,7 @@
 # 3) Check for leaked CONFIG_ symbols
 
 use strict;
+use File::Basename;
 
 my ($dir, $arch, @files) = @ARGV;
 
@@ -99,6 +100,39 @@ sub check_asm_types
 }
 
 my $linux_types;
+my %import_stack = ();
+sub check_include_typesh
+{
+	my $path = $_[0];
+	my $import_path;
+
+	my $fh;
+	my @file_paths = ($path, $dir . "/" .  $path, dirname($filename) . "/" . $path);
+	for my $possible ( @file_paths ) {
+	    if (not $import_stack{$possible} and open($fh, '<', $possible)) {
+		$import_path = $possible;
+		$import_stack{$import_path} = 1;
+		last;
+	    }
+	}
+	if (eof $fh) {
+	    return;
+	}
+
+	my $line;
+	while ($line = <$fh>) {
+		if ($line =~ m/^\s*#\s*include\s+<linux\/types.h>/) {
+			$linux_types = 1;
+			last;
+		}
+		if (my $included = ($line =~ /^\s*#\s*include\s+[<"](\S+)[>"]/)[0]) {
+			check_include_typesh($included);
+		}
+	}
+	close $fh;
+	delete $import_stack{$import_path};
+}
+
 sub check_sizetypes
 {
 	if ($filename =~ /types.h|int-l64.h|int-ll64.h/o) {
@@ -113,6 +147,9 @@ sub check_sizetypes
 		$linux_types = 1;
 		return;
 	}
+	if (my $included = ($line =~ /^\s*#\s*include\s+[<"](\S+)[>"]/)[0]) {
+		check_include_typesh($included);
+	}
 	if ($line =~ m/__[us](8|16|32|64)\b/) {
 		printf STDERR "$filename:$lineno: " .
 		              "found __[us]{8,16,32,64} type " .
@@ -122,4 +159,3 @@ sub check_sizetypes
 		#$ret = 1;
 	}
 }
-