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>

1 files changed, 12 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index c00e5108c0d2..7c79c91662c8 100755
--- 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