[PATCH] checkpatch: don't warn on every struct without const_structs file

[Johannes Berg <johannes@sipsolutions.net>]

From: Johannes Berg <johannes.berg@intel.com>

The script says that it won't warn:
"No structs that should be const will be found [...]"

but then that doesn't work and it warns on every single struct
instead, since the regular expression ends up empty. Fix that
by checking that it's not empty first.

Fixes: bf1fa1dae68e ("checkpatch: externalize the structs that should be const")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 scripts/checkpatch.pl | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a8368d1c4348..722a319acec5 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6010,7 +6010,8 @@ sub process {
 		}
 
 # check for various structs that are normally const (ops, kgdb, device_tree)
-		if ($line !~ /\bconst\b/ &&
+		if ($const_structs ne "" &&
+		    $line !~ /\bconst\b/ &&
 		    $line =~ /\bstruct\s+($const_structs)\b/) {
 			WARN("CONST_STRUCT",
 			     "struct $1 should normally be const\n" .
-- 
2.9.3