From 70dc8a48357ce630d8a76887a9a36f0d34c8caf2 Mon Sep 17 00:00:00 2001
From: Joe Perches <joe@perches.com>
Date: Wed, 11 Sep 2013 14:23:58 -0700
Subject: [PATCH] checkpatch: warn when using extern with function prototypes
 in .h files

Using the extern keyword on function prototypes is superfluous visual
noise so suggest removing it.

Using extern can cause unnecessary line wrapping at 80 columns and
unnecessarily long multi-line function prototypes.

Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 scripts/checkpatch.pl | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7c79c91662c8..e2cb1f4621b7 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3878,6 +3878,16 @@ sub process {
 			}
 		}
 
+# check for new externs in .h files.
+		if ($realfile =~ /\.h$/ &&
+		    $line =~ /^\+\s*(extern\s+)$Type\s*$Ident\s*\(/s) {
+			if (WARN("AVOID_EXTERNS",
+				 "extern prototypes should be avoided in .h files\n" . $herecurr) &&
+			    $fix) {
+				$fixed[$linenr - 1] =~ s/(.*)\bextern\b\s*(.*)/$1$2/;
+			}
+		}
+
 # check for new externs in .c files.
 		if ($realfile =~ /\.c$/ && defined $stat &&
 		    $stat =~ /^.\s*(?:extern\s+)?$Type\s+($Ident)(\s*)\(/s)
-- 
2.39.5