checkpatch: check for duplicate signatures

Emit a warning when a signature is used more than once.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index c00e510..7c79c91 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1544,6 +1544,7 @@ sub process {
        my %suppress_export;
        my $suppress_statement = 0;
 
+       my %signatures = ();
 
        # Pre-scan the patch sanitizing the lines.
        # Pre-scan the patch looking for any __setup documentation.
@@ -1793,6 +1794,17 @@ sub process {
                                             "email address '$email' might be better as '$suggested_email$comment'\n" . $herecurr);
                                }
                        }
+
+# Check for duplicate signatures
+                       my $sig_nospace = $line;
+                       $sig_nospace =~ s/\s//g;
+                       $sig_nospace = lc($sig_nospace);
+                       if (defined $signatures{$sig_nospace}) {
+                               WARN("BAD_SIGN_OFF",
+                                    "Duplicate signature\n" . $herecurr);
+                       } else {
+                               $signatures{$sig_nospace} = 1;
+                       }
                }
 
 # Check for wrappage within a valid hunk of the file