[PATCH] scripts/checkpatch.pl: added test for repeated lines

[Edwin van Vliet <edwin@cheatah.nl>]

Repeated lines may indicate a bug or code that needs clarification. If the
repeated line is intentional, an extra comment may be helpful for reviewers
since the repeated pattern is likely to draw attention.

Signed-off-by: Edwin van Vliet <edwin@cheatah.nl>
---
 scripts/checkpatch.pl |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index b0aa2c6..4b50496 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1479,6 +1479,11 @@ sub process {
 			WARN("adding a line without newline at end of file\n" . $herecurr);
 		}
 
+# check for repeated lines which may indicate bugs or lack of clarity
+		if ($rawline eq $prevrawline) {
+			WARN("repeated line\n" . $herecurr);
+		}
+
 # Blackfin: use hi/lo macros
 		if ($realfile =~ m@arch/blackfin/.*\.S$@) {
 			if ($line =~ /\.[lL][[:space:]]*=.*&[[:space:]]*0x[fF][fF][fF][fF]/) {
-- 
1.7.5.4