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>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ea628eb..6c11cb6 100755 (executable)
--- 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",