[PATCH] checkpatch: Warn when a patch doesn't have a description

[Joe Perches <joe@perches.com>]

Potential patches should have a commit description.
Emit a warning when there isn't one.

Suggested-by: Prakruthi Deepak Heragu <pheragu@codeaurora.org>
Signed-off-by: Joe Perches <joe@perches.com>
---
 scripts/checkpatch.pl | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index b5c875d7132b..8b5f3dae31c9 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2240,6 +2240,7 @@ sub process {
 	my $in_header_lines = $file ? 0 : 1;
 	my $in_commit_log = 0;		#Scanning lines before patch
 	my $has_commit_log = 0;		#Encountered lines before patch
+	my $commit_log_lines = 0;	#Number of commit log lines
 	my $commit_log_possible_stack_dump = 0;
 	my $commit_log_long_line = 0;
 	my $commit_log_has_diff = 0;
@@ -2497,6 +2498,18 @@ sub process {
 
 		$cnt_lines++ if ($realcnt != 0);
 
+# Verify the existence of a commit log if appropriate
+# 2 is used because a $signature is counted in $commit_log_lines
+		if ($in_commit_log) {
+			if ($line !~ /^\s*$/) {
+				$commit_log_lines++;	#could be a $signature
+			}
+		} else if ($has_commit_log && $commit_log_lines < 2) {
+			WARN("COMMIT_MESSAGE",
+			     "Missing commit description - Add an appropriate one\n");
+			$commit_log_lines = 2;	#warn only once
+		}
+
 # Check if the commit log has what seems like a diff which can confuse patch
 		if ($in_commit_log && !$commit_log_has_diff &&
 		    (($line =~ m@^\s+diff\b.*a/[\w/]+@ &&