checkpatch: add --strict preference for #defines using BIT(foo)

Using BIT(foo) and BIT_ULL(bar) is more common now.  Suggest using these
macros over #defines with 1<<value.

Add a --fix option too.

Signed-off-by: Joe Perches <joe@perches.com>
Cc: David Miller <davem@davemloft.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 518cc2e58439..d06b6be2841e 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4975,6 +4975,17 @@ sub process {
                         }
                 }
 
+# check for #defines like: 1 << <digit> that could be BIT(digit)
+                if ($line =~ /#\s*define\s+\w+\s+\(?\s*1\s*([ulUL]*)\s*\<\<\s*(?:\d+|$Ident)\s*\)?/) {
+                        my $ull = "";
+                        $ull = "_ULL" if (defined($1) && $1 =~ /ll/i);
+                        if (CHK("BIT_MACRO",
+                                "Prefer using the BIT$ull macro\n" . $herecurr) &&
+                            $fix) {
+                                $fixed[$fixlinenr] =~ s/\(?\s*1\s*[ulUL]*\s*<<\s*(\d+|$Ident)\s*\)?/BIT${ull}($1)/;
+                        }
+                }
+
 # check for case / default statements not preceded by break/fallthrough/switch
                 if ($line =~ /^.\s*(?:case\s+(?:$Ident|$Constant)\s*|default):/) {
                         my $has_break = 0;