[PATCH v3 1/2] checkpatch: Allow to pass config directory

[PATCH v3 1/2] checkpatch: Allow to pass config directory

[Petr Vorel]

checkpatch.pl searches for .checkpatch.conf in $HOME, $CWD/.scripts
and $CWD.  Allow to pass a single directory via CHECKPATCH_CONFIG_DIR
environment variable. This allows to directly use project configuration
file for projects which vendored checkpatch.pl (e.g. LTP or u-boot).

Although it'd be more convenient for user to add --conf-dir option
(instead of using environment variable), code would get ugly because
options from the configuration file needs to be read before processing
command line options with Getopt::Long.

While at it, document directories and environment variable in help.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
Changes in v3:
* CHECKPATCH_CONFIG_DIR can point to only single directory (':' would
make it not finding the directory, Simon).
* Avoid join undef string (Simon).
* Don't use $ENV{$env_config_dir} twice (Joe).
* Pass new variables to which_conf() instead of using global.

Link to v2:
https://lore.kernel.org/lkml/20260224181623.89904-1-pvorel@suse.cz/

Link to v1:
https://lore.kernel.org/lkml/20260202144221.76765-2-pvorel@suse.cz/

 scripts/checkpatch.pl | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 0492d6afc9a1f..58f3d5a98204c 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -57,6 +57,8 @@ my %ignore_type = ();
 my @ignore = ();
 my $help = 0;
 my $configuration_file = ".checkpatch.conf";
+my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
+my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
 my $max_line_length = 100;
 my $ignore_perl_version = 0;
 my $minimum_perl_version = 5.10.0;
@@ -146,6 +148,11 @@ Options:
   -h, --help, --version      display this help and exit
 
 When FILE is - read standard input.
+
+CONFIGURATION FILE
+Script searches for a configuration file $configuration_file in a directory
+specified by \$$env_config_dir environment variable, or
+(if variable not defined) in path: '$def_configuration_dirs'
 EOM
 
 	exit($exitcode);
@@ -237,7 +244,7 @@ sub list_types {
 	exit($exitcode);
 }
 
-my $conf = which_conf($configuration_file);
+my $conf = which_conf($configuration_file, $env_config_dir, $def_configuration_dirs);
 if (-f $conf) {
 	my @conf_args;
 	open(my $conffile, '<', "$conf")
@@ -1531,9 +1538,12 @@ sub which {
 }
 
 sub which_conf {
-	my ($conf) = @_;
+	my ($conf, $env_key, $paths) = @_;
+	my $env_dir = $ENV{$env_key};
+
+	return "$env_dir/$conf" if (defined($env_dir));
 
-	foreach my $path (split(/:/, ".:$ENV{HOME}:.scripts")) {
+	foreach my $path (split(/:/, $paths)) {
 		if (-e "$path/$conf") {
 			return "$path/$conf";
 		}
-- 
2.53.0

[PATCH v3 2/2] checkpatch: Add option to not force /* */ for SPDX

[Petr Vorel]

Add option --ignore-old-toolchain to not force /* */ for SPDX.

As documented in aa19a176df95d6, this is required for some old
toolchains still have older assembler tools which cannot handle C++
style comments. This allows avoid forcing this for for projects which
vendored checkpatch.pl (e.g. LTP or u-boot).

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
New in v3.

I suppose you will not want to add code which should not be used on
mainline. But it would help to not force other projects which vendored
checkpatch.pl to neither force /* */ nor carry extra patch.

I wonder if this rule is still relevant (are these old toolchains still
being used).

Kind regards,
Petr

 scripts/checkpatch.pl | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 58f3d5a98204c..ec1e9670a0c1d 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -61,6 +61,7 @@ my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
 my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
 my $max_line_length = 100;
 my $ignore_perl_version = 0;
+my $ignore_old_toolchain = 0;
 my $minimum_perl_version = 5.10.0;
 my $min_conf_desc_length = 4;
 my $spelling_file = "$D/spelling.txt";
@@ -137,6 +138,9 @@ Options:
                              file.  It's your fault if there's no backup or git
   --ignore-perl-version      override checking of perl version.  expect
                              runtime errors.
+  --ignore-old-toolchain     don't force C++ comments (/* */) for SPDX license
+                             (required by old toolchains). NOTE: it should *not*
+                             be used for Linux mainline.
   --codespell                Use the codespell dictionary for spelling/typos
                              (default:$codespellfile)
   --codespellfile            Use this codespell dictionary
@@ -346,6 +350,7 @@ GetOptions(
 	'fix!'		=> \$fix,
 	'fix-inplace!'	=> \$fix_inplace,
 	'ignore-perl-version!' => \$ignore_perl_version,
+	'ignore-old-toolchain!' => \$ignore_old_toolchain,
 	'debug=s'	=> \%debug,
 	'test-only=s'	=> \$tst_only,
 	'codespell!'	=> \$codespell,
@@ -3812,7 +3817,7 @@ sub process {
 			} elsif ($rawline =~ /^\+/) {
 				my $comment = "";
 				if ($realfile =~ /\.(h|s|S)$/) {
-					$comment = '/*';
+					$comment = $ignore_old_toolchain ? '//' : '/*';
 				} elsif ($realfile =~ /\.(c|rs|dts|dtsi)$/) {
 					$comment = '//';
 				} elsif (($checklicenseline == 2) || $realfile =~ /\.(sh|pl|py|awk|tc|yaml)$/) {
-- 
2.53.0

Re: [PATCH v3 2/2] checkpatch: Add option to not force /* */ for SPDX

[Simon Glass]

Hi Petr,

On Wed, 8 Apr 2026 at 06:06, Petr Vorel <pvorel@suse.cz> wrote:
>
> Add option --ignore-old-toolchain to not force /* */ for SPDX.
>
> As documented in aa19a176df95d6, this is required for some old
> toolchains still have older assembler tools which cannot handle C++
> style comments. This allows avoid forcing this for for projects which
> vendored checkpatch.pl (e.g. LTP or u-boot).
>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> New in v3.
>
> I suppose you will not want to add code which should not be used on
> mainline. But it would help to not force other projects which vendored
> checkpatch.pl to neither force /* */ nor carry extra patch.
>
> I wonder if this rule is still relevant (are these old toolchains still
> being used).
>
> Kind regards,
> Petr
>
>  scripts/checkpatch.pl | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 58f3d5a98204c..ec1e9670a0c1d 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -61,6 +61,7 @@ my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
>  my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
>  my $max_line_length = 100;
>  my $ignore_perl_version = 0;
> +my $ignore_old_toolchain = 0;
>  my $minimum_perl_version = 5.10.0;
>  my $min_conf_desc_length = 4;
>  my $spelling_file = "$D/spelling.txt";
> @@ -137,6 +138,9 @@ Options:
>                               file.  It's your fault if there's no backup or git
>    --ignore-perl-version      override checking of perl version.  expect
>                               runtime errors.
> +  --ignore-old-toolchain     don't force C++ comments (/* */) for SPDX license
> +                             (required by old toolchains). NOTE: it should *not*
> +                             be used for Linux mainline.
>    --codespell                Use the codespell dictionary for spelling/typos
>                               (default:$codespellfile)
>    --codespellfile            Use this codespell dictionary
> @@ -346,6 +350,7 @@ GetOptions(
>         'fix!'          => \$fix,
>         'fix-inplace!'  => \$fix_inplace,
>         'ignore-perl-version!' => \$ignore_perl_version,
> +       'ignore-old-toolchain!' => \$ignore_old_toolchain,
>         'debug=s'       => \%debug,
>         'test-only=s'   => \$tst_only,
>         'codespell!'    => \$codespell,
> @@ -3812,7 +3817,7 @@ sub process {
>                         } elsif ($rawline =~ /^\+/) {
>                                 my $comment = "";
>                                 if ($realfile =~ /\.(h|s|S)$/) {
> -                                       $comment = '/*';
> +                                       $comment = $ignore_old_toolchain ? '//' : '/*';
>                                 } elsif ($realfile =~ /\.(c|rs|dts|dtsi)$/) {
>                                         $comment = '//';
>                                 } elsif (($checklicenseline == 2) || $realfile =~ /\.(sh|pl|py|awk|tc|yaml)$/) {
> --
> 2.53.0
>

Is the help text swapped? To my mind /* */ is C-style.

The option name is quite generic for something that only controls SPDX
comment style - how about --spdx-cxx-comments ?

Regards,
Simon

Re: [PATCH v3 1/2] checkpatch: Allow to pass config directory

[Simon Glass]

Hi Petr,

On Wed, 8 Apr 2026 at 06:06, Petr Vorel <pvorel@suse.cz> wrote:
>
> checkpatch.pl searches for .checkpatch.conf in $HOME, $CWD/.scripts
> and $CWD.  Allow to pass a single directory via CHECKPATCH_CONFIG_DIR
> environment variable. This allows to directly use project configuration
> file for projects which vendored checkpatch.pl (e.g. LTP or u-boot).
>
> Although it'd be more convenient for user to add --conf-dir option
> (instead of using environment variable), code would get ugly because
> options from the configuration file needs to be read before processing
> command line options with Getopt::Long.
>
> While at it, document directories and environment variable in help.
>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> Changes in v3:
> * CHECKPATCH_CONFIG_DIR can point to only single directory (':' would
> make it not finding the directory, Simon).
> * Avoid join undef string (Simon).
> * Don't use $ENV{$env_config_dir} twice (Joe).
> * Pass new variables to which_conf() instead of using global.
>
> Link to v2:
> https://lore.kernel.org/lkml/20260224181623.89904-1-pvorel@suse.cz/
>
> Link to v1:
> https://lore.kernel.org/lkml/20260202144221.76765-2-pvorel@suse.cz/
>
>  scripts/checkpatch.pl | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 0492d6afc9a1f..58f3d5a98204c 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -57,6 +57,8 @@ my %ignore_type = ();
>  my @ignore = ();
>  my $help = 0;
>  my $configuration_file = ".checkpatch.conf";
> +my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
> +my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
>  my $max_line_length = 100;
>  my $ignore_perl_version = 0;
>  my $minimum_perl_version = 5.10.0;
> @@ -146,6 +148,11 @@ Options:
>    -h, --help, --version      display this help and exit
>
>  When FILE is - read standard input.
> +
> +CONFIGURATION FILE
> +Script searches for a configuration file $configuration_file in a directory
> +specified by \$$env_config_dir environment variable, or
> +(if variable not defined) in path: '$def_configuration_dirs'
>  EOM
>
>         exit($exitcode);
> @@ -237,7 +244,7 @@ sub list_types {
>         exit($exitcode);
>  }
>
> -my $conf = which_conf($configuration_file);
> +my $conf = which_conf($configuration_file, $env_config_dir, $def_configuration_dirs);
>  if (-f $conf) {
>         my @conf_args;
>         open(my $conffile, '<', "$conf")
> @@ -1531,9 +1538,12 @@ sub which {
>  }
>
>  sub which_conf {
> -       my ($conf) = @_;
> +       my ($conf, $env_key, $paths) = @_;
> +       my $env_dir = $ENV{$env_key};
> +
> +       return "$env_dir/$conf" if (defined($env_dir));
>
> -       foreach my $path (split(/:/, ".:$ENV{HOME}:.scripts")) {
> +       foreach my $path (split(/:/, $paths)) {
>                 if (-e "$path/$conf") {
>                         return "$path/$conf";
>                 }
> --
> 2.53.0
>

Reviewed-by: Simon Glass <sjg@chromium.org>

Some nits:

When CHECKPATCH_CONFIG_DIR is set but the file doesn't exist there,
the default paths are silently skipped. A warning would help catch
typos.

The commit message says the search order is "$HOME, $CWD/.scripts and
$CWD" but the code has ".:$HOME:.scripts" (CWD first).

'Allow to pass' -> 'Allow passing'

Regards,
Simon

Re: [PATCH v3 1/2] checkpatch: Allow to pass config directory

[Petr Vorel]

> Hi Petr,

> On Wed, 8 Apr 2026 at 06:06, Petr Vorel <pvorel@suse.cz> wrote:

> > checkpatch.pl searches for .checkpatch.conf in $HOME, $CWD/.scripts
> > and $CWD.  Allow to pass a single directory via CHECKPATCH_CONFIG_DIR
> > environment variable. This allows to directly use project configuration
> > file for projects which vendored checkpatch.pl (e.g. LTP or u-boot).

> > Although it'd be more convenient for user to add --conf-dir option
> > (instead of using environment variable), code would get ugly because
> > options from the configuration file needs to be read before processing
> > command line options with Getopt::Long.

> > While at it, document directories and environment variable in help.

> > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > ---
> > Changes in v3:
> > * CHECKPATCH_CONFIG_DIR can point to only single directory (':' would
> > make it not finding the directory, Simon).
> > * Avoid join undef string (Simon).
> > * Don't use $ENV{$env_config_dir} twice (Joe).
> > * Pass new variables to which_conf() instead of using global.

> > Link to v2:
> > https://lore.kernel.org/lkml/20260224181623.89904-1-pvorel@suse.cz/

> > Link to v1:
> > https://lore.kernel.org/lkml/20260202144221.76765-2-pvorel@suse.cz/

> >  scripts/checkpatch.pl | 16 +++++++++++++---
> >  1 file changed, 13 insertions(+), 3 deletions(-)

> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index 0492d6afc9a1f..58f3d5a98204c 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -57,6 +57,8 @@ my %ignore_type = ();
> >  my @ignore = ();
> >  my $help = 0;
> >  my $configuration_file = ".checkpatch.conf";
> > +my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
> > +my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
> >  my $max_line_length = 100;
> >  my $ignore_perl_version = 0;
> >  my $minimum_perl_version = 5.10.0;
> > @@ -146,6 +148,11 @@ Options:
> >    -h, --help, --version      display this help and exit

> >  When FILE is - read standard input.
> > +
> > +CONFIGURATION FILE
> > +Script searches for a configuration file $configuration_file in a directory
> > +specified by \$$env_config_dir environment variable, or
> > +(if variable not defined) in path: '$def_configuration_dirs'
> >  EOM

> >         exit($exitcode);
> > @@ -237,7 +244,7 @@ sub list_types {
> >         exit($exitcode);
> >  }

> > -my $conf = which_conf($configuration_file);
> > +my $conf = which_conf($configuration_file, $env_config_dir, $def_configuration_dirs);
> >  if (-f $conf) {
> >         my @conf_args;
> >         open(my $conffile, '<', "$conf")
> > @@ -1531,9 +1538,12 @@ sub which {
> >  }

> >  sub which_conf {
> > -       my ($conf) = @_;
> > +       my ($conf, $env_key, $paths) = @_;
> > +       my $env_dir = $ENV{$env_key};
> > +
> > +       return "$env_dir/$conf" if (defined($env_dir));

> > -       foreach my $path (split(/:/, ".:$ENV{HOME}:.scripts")) {
> > +       foreach my $path (split(/:/, $paths)) {
> >                 if (-e "$path/$conf") {
> >                         return "$path/$conf";
> >                 }
> > --
> > 2.53.0


> Reviewed-by: Simon Glass <sjg@chromium.org>

Thank you! I'll probably send v4, but I will not dare to add your RBT due
changes I will add. Thanks for a careful review!

> Some nits:

> When CHECKPATCH_CONFIG_DIR is set but the file doesn't exist there,
> the default paths are silently skipped. A warning would help catch
> typos.

I was thinking about it as well. Probably worth to add it => v4.

> The commit message says the search order is "$HOME, $CWD/.scripts and
> $CWD" but the code has ".:$HOME:.scripts" (CWD first).

+1, thanks!

> 'Allow to pass' -> 'Allow passing'

+1, thanks!

Kind regards,
Petr

> Regards,
> Simon

Re: [PATCH v3 2/2] checkpatch: Add option to not force /* */ for SPDX

[Petr Vorel]

> Hi Petr,

> On Wed, 8 Apr 2026 at 06:06, Petr Vorel <pvorel@suse.cz> wrote:

> > Add option --ignore-old-toolchain to not force /* */ for SPDX.

> > As documented in aa19a176df95d6, this is required for some old
> > toolchains still have older assembler tools which cannot handle C++
> > style comments. This allows avoid forcing this for for projects which
> > vendored checkpatch.pl (e.g. LTP or u-boot).

> > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > ---
> > New in v3.

> > I suppose you will not want to add code which should not be used on
> > mainline. But it would help to not force other projects which vendored
> > checkpatch.pl to neither force /* */ nor carry extra patch.

> > I wonder if this rule is still relevant (are these old toolchains still
> > being used).

> > Kind regards,
> > Petr

> >  scripts/checkpatch.pl | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)

> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index 58f3d5a98204c..ec1e9670a0c1d 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -61,6 +61,7 @@ my $def_configuration_dirs = ".:$ENV{HOME}:.scripts";
> >  my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
> >  my $max_line_length = 100;
> >  my $ignore_perl_version = 0;
> > +my $ignore_old_toolchain = 0;
> >  my $minimum_perl_version = 5.10.0;
> >  my $min_conf_desc_length = 4;
> >  my $spelling_file = "$D/spelling.txt";
> > @@ -137,6 +138,9 @@ Options:
> >                               file.  It's your fault if there's no backup or git
> >    --ignore-perl-version      override checking of perl version.  expect
> >                               runtime errors.
> > +  --ignore-old-toolchain     don't force C++ comments (/* */) for SPDX license
> > +                             (required by old toolchains). NOTE: it should *not*
> > +                             be used for Linux mainline.
> >    --codespell                Use the codespell dictionary for spelling/typos
> >                               (default:$codespellfile)
> >    --codespellfile            Use this codespell dictionary
> > @@ -346,6 +350,7 @@ GetOptions(
> >         'fix!'          => \$fix,
> >         'fix-inplace!'  => \$fix_inplace,
> >         'ignore-perl-version!' => \$ignore_perl_version,
> > +       'ignore-old-toolchain!' => \$ignore_old_toolchain,
> >         'debug=s'       => \%debug,
> >         'test-only=s'   => \$tst_only,
> >         'codespell!'    => \$codespell,
> > @@ -3812,7 +3817,7 @@ sub process {
> >                         } elsif ($rawline =~ /^\+/) {
> >                                 my $comment = "";
> >                                 if ($realfile =~ /\.(h|s|S)$/) {
> > -                                       $comment = '/*';
> > +                                       $comment = $ignore_old_toolchain ? '//' : '/*';
> >                                 } elsif ($realfile =~ /\.(c|rs|dts|dtsi)$/) {
> >                                         $comment = '//';
> >                                 } elsif (($checklicenseline == 2) || $realfile =~ /\.(sh|pl|py|awk|tc|yaml)$/) {
> > --
> > 2.53.0


> Is the help text swapped? To my mind /* */ is C-style.

+1, thanks for catching this.

> The option name is quite generic for something that only controls SPDX
> comment style - how about --spdx-cxx-comments ?

Good point, I'll change it in v4.

Kind regards,
Petr

> Regards,
> Simon