From 27fdce43084d5c12ebb527e5b70a5fe1a763a355 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 7c79c91662c80..e2cb1f4621b7e 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