checkpatch: improve octal permissions test speed

The current octal permissions test is very slow.

When patch ("checkpatch: add checks for constant non-octal permissions")
was added, processing time approximately tripled.

Regain almost all of the performance by not looping through all the
possible functions unless the line contains one of the functions.

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 3d3ef2ff62b2965d892f0ea31817a6e927107376..9f03345a1c5cdc7e9ac22ed3f17306729681c00d 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -388,6 +388,13 @@ our @mode_permission_funcs = (
        ["(?:CLASS|DEVICE|SENSOR)_ATTR", 2],
 );
 
+#Create a search pattern for all these functions to speed up a loop below
+our $mode_perms_search = "";
+foreach my $entry (@mode_permission_funcs) {
+       $mode_perms_search .= '|' if ($mode_perms_search ne "");
+       $mode_perms_search .= $entry->[0];
+}
+
 our $allowed_asm_includes = qr{(?x:
        irq|
        memory
@@ -4524,26 +4531,30 @@ sub process {
                             "Exporting world writable files is usually an error. Consider more restrictive permissions.\n" . $herecurr);
                }
 
-               foreach my $entry (@mode_permission_funcs) {
-                       my $func = $entry->[0];
-                       my $arg_pos = $entry->[1];
-
-                       my $skip_args = "";
-                       if ($arg_pos > 1) {
-                               $arg_pos--;
-                               $skip_args = "(?:\\s*$FuncArg\\s*,\\s*){$arg_pos,$arg_pos}";
-                       }
-                       my $test = "\\b$func\\s*\\(${skip_args}([\\d]+)\\s*[,\\)]";
-                       if ($^V && $^V ge 5.10.0 &&
-                           $line =~ /$test/) {
-                               my $val = $1;
-                               $val = $6 if ($skip_args ne "");
-
-                               if ($val !~ /^0$/ &&
-                                   (($val =~ /^$Int$/ && $val !~ /^$Octal$/) ||
-                                    length($val) ne 4)) {
-                                       ERROR("NON_OCTAL_PERMISSIONS",
-                                             "Use 4 digit octal (0777) not decimal permissions\n" . $herecurr);
+# Mode permission misuses where it seems decimal should be octal
+# This uses a shortcut match to avoid unnecessary uses of a slow foreach loop
+               if ($^V && $^V ge 5.10.0 &&
+                   $line =~ /$mode_perms_search/) {
+                       foreach my $entry (@mode_permission_funcs) {
+                               my $func = $entry->[0];
+                               my $arg_pos = $entry->[1];
+
+                               my $skip_args = "";
+                               if ($arg_pos > 1) {
+                                       $arg_pos--;
+                                       $skip_args = "(?:\\s*$FuncArg\\s*,\\s*){$arg_pos,$arg_pos}";
+                               }
+                               my $test = "\\b$func\\s*\\(${skip_args}([\\d]+)\\s*[,\\)]";
+                               if ($line =~ /$test/) {
+                                       my $val = $1;
+                                       $val = $6 if ($skip_args ne "");
+
+                                       if ($val !~ /^0$/ &&
+                                           (($val =~ /^$Int$/ && $val !~ /^$Octal$/) ||
+                                            length($val) ne 4)) {
+                                               ERROR("NON_OCTAL_PERMISSIONS",
+                                                     "Use 4 digit octal (0777) not decimal permissions\n" . $herecurr);
+                                       }
                                }
                        }
                }