[PATCH] checkpatch: Ignore some octal permissions of 0

[Joe Perches]

module_param and create_proc uses with a permissions use of a single 0
are "special" and should not emit any warning.

module_param uses with permission 0 is not visible in sysfs
create_proc uses with permission 0 uses a default permission

Signed-off-by: Bartosz Golaszewski <brgl@xxxxxxxx>
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---
 scripts/checkpatch.pl | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 6b130a4116fa..2db1d0363ce2 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6298,6 +6298,10 @@ sub process {
 
 # Mode permission misuses where it seems decimal should be octal
 # This uses a shortcut match to avoid unnecessary uses of a slow foreach loop
+# o Ignore module_param*(...) uses with a decimal 0 permission as that has a
+#   specific definition of not visible in sysfs.
+# o Ignore proc_create*(...) uses with a decimal 0 permission as that means
+#   use the default permissions
 		if ($^V && $^V ge 5.10.0 &&
 		    defined $stat &&
 		    $line =~ /$mode_perms_search/) {
@@ -6321,8 +6325,9 @@ sub process {
 				if ($stat =~ /$test/) {
 					my $val = $1;
 					$val = $6 if ($skip_args ne "");
-					if (($val =~ /^$Int$/ && $val !~ /^$Octal$/) ||
-					    ($val =~ /^$Octal$/ && length($val) ne 4)) {
+					if (!($func =~ /^(?:module_param|proc_create)/ && $val eq "0") &&
+					    (($val =~ /^$Int$/ && $val !~ /^$Octal$/) ||
+					     ($val =~ /^$Octal$/ && length($val) ne 4))) {
 						ERROR("NON_OCTAL_PERMISSIONS",
 						      "Use 4 digit octal (0777) not decimal permissions\n" . "$here\n" . $stat_real);
 					}
-- 
2.15.0