[PATCH] checkpatch: Warn on comparisons to true and false

[Joe Perches]

Comparisons of A to true and false are better written
as A and !A.

Bleat a message on use.

Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---
 scripts/checkpatch.pl | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 3fb6d86..080e7f6 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3538,6 +3538,23 @@ sub process {
 			     "Using yield() is generally wrong. See yield() kernel-doc (sched/core.c)\n"  . $herecurr);
 		}
 
+# check for comparisons against true and false
+		if ($line =~ /\+\s*(.*?)($Lval)\s*(==|\!=)\s*(true|false)\b(.*)$/i) {
+			my $lead = $1;
+			my $arg = $2;
+			my $test = $3;
+			my $otype = $4;
+			my $trail = $5;
+			my $type = lc($otype);
+			my $op = "!";
+			if (("$test" eq "==" && "$type" eq "true") ||
+			    ("$test" eq "!=" && "$type" eq "false")) {
+				$op = "";
+			}
+			WARN("BOOL_COMPARISON",
+			     "Using comparison to $otype is poor style. Use '${lead}${op}${arg}${trail}'\n" . $herecurr);
+		}
+
 # check for semaphores initialized locked
 		if ($line =~ /^.\s*sema_init.+,\W?0\W?\)/) {
 			WARN("CONSIDER_COMPLETION",


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/