checkpatch: emit a warning on file add/move/delete

Whenever files are added, moved, or deleted, the MAINTAINERS file
patterns can be out of sync or outdated.

To try to keep MAINTAINERS more up-to-date, add a one-time warning
whenever a patch does any of those.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20180430124651.10340-5-stefanha@redhat.com
(cherry picked from commit 13f1937ef33950b1112049972249e6191b82e6c9)
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>

Conflicts:
  QEMU WARN() only takes one argument, drop the 'type' value in the
  first argument.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

scripts/checkpatch.pl

@@ -1185,7 +1185,7 @@ sub process {
 
 	my $in_header_lines = $file ? 0 : 1;
 	my $in_commit_log = 0;		#Scanning lines before patch
-
+	my $reported_maintainer_file = 0;
 	my $non_utf8_charset = 0;
 
 	our @report = ();
@@ -1390,6 +1390,16 @@ sub process {
 			}
 		}
 
+# Check for added, moved or deleted files
+		if (!$reported_maintainer_file && !$in_commit_log &&
+		    ($line =~ /^(?:new|deleted) file mode\s*\d+\s*$/ ||
+		     $line =~ /^rename (?:from|to) [\w\/\.\-]+\s*$/ ||
+		     ($line =~ /\{\s*([\w\/\.\-]*)\s*\=\>\s*([\w\/\.\-]*)\s*\}/ &&
+		      (defined($1) || defined($2))))) {
+			$reported_maintainer_file = 1;
+			WARN("added, moved or deleted file(s), does MAINTAINERS need updating?\n" . $herecurr);
+		}
+
 # Check for wrappage within a valid hunk of the file
 		if ($realcnt != 0 && $line !~ m{^(?:\+|-| |\\ No newline|$)}) {
 			ERROR("patch seems to be corrupt (line wrapped?)\n" .