checkpatch: add PREFER_IS_ENABLED test

Using #if defined CONFIG_<FOO> || defined CONFIG_<FOO>_MODULE is
more verbose than necessary and IS_ENABLED(CONFIG_<FOO>) is preferred.

So add a test and a message for it.

--fix it to if desired.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d574d13ba96395ffa0c3a73b9ce669ba42e6a5a3..eb8f88787e81f0f0036c0cbc4bf23c70b4465a10 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -5637,6 +5637,16 @@ sub process {
                        }
                }
 
+# check for #if defined CONFIG_<FOO> || defined CONFIG_<FOO>_MODULE
+               if ($line =~ /^\+\s*#\s*if\s+defined(?:\s*\(?\s*|\s+)(CONFIG_[A-Z_]+)\s*\)?\s*\|\|\s*defined(?:\s*\(?\s*|\s+)\1_MODULE\s*\)?\s*$/) {
+                       my $config = $1;
+                       if (WARN("PREFER_IS_ENABLED",
+                                "Prefer IS_ENABLED(<FOO>) to CONFIG_<FOO> || CONFIG_<FOO>_MODULE\n" . $herecurr) &&
+                           $fix) {
+                               $fixed[$fixlinenr] = "\+#if IS_ENABLED($config)";
+                       }
+               }
+
 # check for case / default statements not preceded by break/fallthrough/switch
                if ($line =~ /^.\s*(?:case\s+(?:$Ident|$Constant)\s*|default):/) {
                        my $has_break = 0;