[PATCH v6 0/4] checkpatch: userspace improvements

[PATCH v6 0/4] checkpatch: userspace improvements

[Petr Vorel]

Few improvements for user space code + --userspace option for projects
which vendored checkpatch.pl.

There could be probably more checks which are kernel space only.

v6:
- Remove 4th commit "checkpatch: Factor out the check for UAPI files"
  which added is_uapi(), which was wrong. I overlook that regex on BIT()
  macro is different from the others, matching only ^include/uapi/.
- Fix 5th commit which wrongly called is_uapi() instead of
  is_userspace().

Link to v5:
https://lore.kernel.org/lkml/20260901105642.851234-1-pvorel@suse.cz/

Link to v4:
https://lore.kernel.org/lkml/20260810164552.1049483-1-pvorel@suse.cz/


Petr Vorel (4):
  checkpatch: Add more userspace directories to is_userspace()
  checkpatch: Ignore <inttypes.h> format macros for userspace tools
  checkpatch: Add --userspace to force userspace rules
  checkpatch: Skip kernel specific checks for userspace

 scripts/checkpatch.pl | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

-- 
2.55.0

[PATCH v6 1/4] checkpatch: Add more userspace directories to is_userspace()

[Petr Vorel]

arch/ directory contains subdirectories with userspace tools (at least
arch/*/tools/ and arch/*/boot/tools/). Add check to consider any
arch/.*/tools/ subdirectory as userspace tools directory.

This helps not only to strscpy() checks but also to CamelCase checks in
the next commit to be more precise.

Follow-up: 99b70ece33d8 ("checkpatch: suppress strscpy warnings for userspace tools")
Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
The same as in v5.

 scripts/checkpatch.pl | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index f424dafce5bc..b8702f6bc9b5 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2667,7 +2667,9 @@ sub exclude_global_initialisers {
 
 sub is_userspace {
     my ($realfile) = @_;
-    return ($realfile =~ m@^tools/@ || $realfile =~ m@^scripts/@);
+    return ($realfile =~ m@^tools/@ ||
+		$realfile =~ m@^scripts/@ ||
+		$realfile =~ m@^arch/.*/tools/@);
 }
 
 sub process {
-- 
2.55.0

[PATCH v6 2/4] checkpatch: Ignore <inttypes.h> format macros for userspace tools

[Petr Vorel]

Constants from <inttypes.h> are used only in userspace tools, they are
from ISO C99, let's don't report it:

    arch/mips/boot/tools/relocs.c:572: CHECK: Avoid CamelCase: <PRIx32>
    arch/s390/tools/relocs.c:52: CHECK: Avoid CamelCase: <PRIu64>
    tools/testing/selftests/mm/vm_util.c:244: CHECK: Avoid CamelCase: <SCNu64>

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
The same as in v5 and earlier versions.

 scripts/checkpatch.pl | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index b8702f6bc9b5..b458c7f22684 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -5950,6 +5950,8 @@ sub process {
 #Ignore SI style variants like nS, mV and dB
 #(ie: max_uV, regulator_min_uA_show, RANGE_mA_VALUE)
 			    $var !~ /^(?:[a-z0-9_]*|[A-Z0-9_]*)?_?[a-z][A-Z](?:_[a-z0-9_]+|_[A-Z0-9_]+)?$/ &&
+#Ignore <inttypes.h> format macros (e.g. PRIu64, SCNu64)
+			    (is_userspace($realfile) ? $var !~ /^(?:PRI|SCN)[dioux][A-Z0-9]+$/ : 1) &&
 #Ignore some three character SI units explicitly, like MiB and KHz
 			    $var !~ /^(?:[a-z_]*?)_?(?:[KMGT]iB|[KMGT]?Hz)(?:_[a-z_]+)?$/) {
 				while ($var =~ m{\b($Ident)}g) {
-- 
2.55.0

[PATCH v6 3/4] checkpatch: Add --userspace to force userspace rules

[Petr Vorel]

Also allow to use --no-userspace for userspace projects which vendored
checkpatch.pl and use --userspace globally to be able switch it off for
files with kernel code.

Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
The same as in v5.

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

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index b458c7f22684..ead35e6abba7 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -63,6 +63,7 @@ my $env_config_dir = 'CHECKPATCH_CONFIG_DIR';
 my $max_line_length = 100;
 my $ignore_perl_version = 0;
 my $spdx_cxx_comments = 0;
+my $userspace;
 my $minimum_perl_version = 5.10.0;
 my $min_conf_desc_length = 4;
 my $spelling_file = "$D/spelling.txt";
@@ -143,6 +144,7 @@ Options:
                              (required by old toolchains), allow also C++
                              comments (//).
                              NOTE: it should *not* be used for Linux mainline.
+  --userspace                Force rules specific for userspace.
   --codespell                Use the codespell dictionary for spelling/typos
                              (default:$codespellfile)
   --codespellfile            Use this codespell dictionary
@@ -358,6 +360,7 @@ GetOptions(
 	'codespell!'	=> \$codespell,
 	'codespellfile=s'	=> \$user_codespellfile,
 	'typedefsfile=s'	=> \$typedefsfile,
+	'userspace!'	=> \$userspace,
 	'color=s'	=> \$color,
 	'no-color'	=> \$color,	#keep old behaviors of -nocolor
 	'nocolor'	=> \$color,	#keep old behaviors of -nocolor
@@ -2667,6 +2670,9 @@ sub exclude_global_initialisers {
 
 sub is_userspace {
     my ($realfile) = @_;
+
+    return $userspace if (defined $userspace);
+
     return ($realfile =~ m@^tools/@ ||
 		$realfile =~ m@^scripts/@ ||
 		$realfile =~ m@^arch/.*/tools/@);
-- 
2.55.0

[PATCH v6 4/4] checkpatch: Skip kernel specific checks for userspace

[Petr Vorel]

These check are kernel specific, do not warn about it when testing
userspace code:

* BIT_MACRO
* LONG_UDELAY
* MSLEEP
* PREFER_KERNEL_TYPES
* USLEEP_RANGE

Follow-up: 99b70ece33d8 ("checkpatch: suppress strscpy warnings for userspace tools")
Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
v6: Fix: use is_userspace instead of is_uapi().

 scripts/checkpatch.pl | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ead35e6abba7..3614cfe4dcbb 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6696,7 +6696,8 @@ sub process {
 		}
 
 # prefer usleep_range over udelay
-		if ($line =~ /\budelay\s*\(\s*(\d+)\s*\)/) {
+		if (!is_userspace($realfile) &&
+			$line =~ /\budelay\s*\(\s*(\d+)\s*\)/) {
 			my $delay = $1;
 			# ignore udelay's < 10, however
 			if (! ($delay < 10) ) {
@@ -6710,7 +6711,8 @@ sub process {
 		}
 
 # warn about unexpectedly long msleep's
-		if ($line =~ /\bmsleep\s*\((\d+)\);/) {
+		if (!is_userspace($realfile) &&
+			$line =~ /\bmsleep\s*\((\d+)\);/) {
 			if ($1 < 20) {
 				WARN("MSLEEP",
 				     "msleep < 20ms can sleep for up to 20ms; see function description of msleep().\n" . $herecurr);
@@ -6932,7 +6934,7 @@ sub process {
 
 # check for c99 types like uint8_t used outside of uapi/ and tools/
 		if ($realfile !~ m@\binclude/uapi/@ &&
-		    $realfile !~ m@\btools/@ &&
+		    !is_userspace($realfile) &&
 		    $line =~ /\b($Declare)\s*$Ident\s*[=;,\[]/) {
 			my $type = $1;
 			if ($type =~ /\b($typeC99Typedefs)\b/) {
@@ -7182,6 +7184,7 @@ sub process {
 # check usleep_range arguments
 		if ($perl_version_ok &&
 		    defined $stat &&
+		    !is_userspace($realfile) &&
 		    $stat =~ /^\+(?:.*?)\busleep_range\s*\(\s*($FuncArg)\s*,\s*($FuncArg)\s*\)/) {
 			my $min = $1;
 			my $max = $7;
@@ -7425,6 +7428,7 @@ sub process {
 
 # check for #defines like: 1 << <digit> that could be BIT(digit), it is not exported to uapi
 		if ($realfile !~ m@^include/uapi/@ &&
+		    !is_userspace($realfile) &&
 		    $line =~ /#\s*define\s+\w+\s+\(?\s*1\s*([ulUL]*)\s*\<\<\s*(?:\d+|$Ident)\s*\)?/) {
 			my $ull = "";
 			$ull = "_ULL" if (defined($1) && $1 =~ /ll/i);
-- 
2.55.0

Re: [PATCH v6 0/4] checkpatch: userspace improvements

[Andrew Morton]

On Fri,  4 Sep 2026 13:02:26 +0200 Petr Vorel <pvorel@suse.cz> wrote:

> Few improvements for user space code + --userspace option for projects
> which vendored checkpatch.pl.
> 
> There could be probably more checks which are kernel space only.

Thanks.  Let me put this into mm.git's mm-nonmm-unstable branch (and
hence into linux-next) for testing and additional review.

> Follow-up: 99b70ece33d8 ("checkpatch: suppress strscpy warnings for userspace tools")

Sorry, I'm not a fan of inventing new tags.  This isn't a documented
tag and nobody has ever used it before.  I altered these to

: This is a follow-up to 99b70ece33d8 ("checkpatch: suppress strscpy
: warnings for userspace tools").