checkpatch: add 'Prefer ARRAY_SIZE" test

Add a test for sizeof(foo)/sizeof(foo[0]) that could be ARRAY_SIZE(foo).

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>

1 files changed, 13 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ea628ebfa20e..6c11cb61e9f4 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3227,6 +3227,19 @@ sub process {
                                 $herecurr);
                }
 
+# check for sizeof(foo)/sizeof(foo[0]) that could be ARRAY_SIZE(foo)
+                if ($line =~ m@\bsizeof\s*\(\s*($Lval)\s*\)@) {
+                        my $array = $1;
+                        if ($line =~ m@\b(sizeof\s*\(\s*\Q$array\E\s*\)\s*/\s*sizeof\s*\(\s*\Q$array\E\s*\[\s*0\s*\]\s*\))@) {
+                                my $array_div = $1;
+                                if (WARN("ARRAY_SIZE",
+                                         "Prefer ARRAY_SIZE($array)\n" . $herecurr) &&
+                                    $fix) {
+                                        $fixed[$fixlinenr] =~ s/\Q$array_div\E/ARRAY_SIZE($array)/;
+                                }
+                        }
+                }
+
 # check for function declarations without arguments like "int foo()"
                 if ($line =~ /(\b$Type\s+$Ident)\s*\(\s*\)/) {
                         if (ERROR("FUNCTION_WITHOUT_ARGS",