[RFC PATCH] checkpatch: Warn on patch subjects with "checkpatch"

[Joe Perches <joe@perches.com>]

I think patch subject lines with "checkpatch" in
them are almost never really useful.

Maybe a new checkpatch test to see if a subject line
is perhaps less than informational should be added.

Something like:
---
 scripts/checkpatch.pl | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 31a731e..a690515 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2048,6 +2048,13 @@ sub process {
 			$in_commit_log = 0;
 		}
 
+# Check patch subject lines for "checkpatch" (but not checkpatch:)
+		if ($in_header_lines &&
+		    $line =~ /^\s*subject:.*\bcheckpatch(?!(?:\.pl)?:)\b/i) {
+			WARN("BAD_PATCH_SUBJECT",
+			     "Patch subjects with 'checkpatch' are not generally useful.  Describe the change, not the tool that suggests the change.\n" . $herecurr);
+		}
+
 # Check signature styles
 		if (!$in_header_lines &&
 		    $line =~ /^(\s*)([a-z0-9_-]+by:|$signature_tags)(\s*)(.*)/i) {