[Linux-kernel-mentees] [PATCH v7 0/2] checkpatch: add verbose mode

[Linux-kernel-mentees] [PATCH v7 0/2] checkpatch: add verbose mode

[Dwaipayan Ray]

Add a new verbose mode to checkpatch. The verbose test
descriptions are read from the checkpatch documentation
file at `Documentation/dev-tools/checkpatch.rst`.

The verbose mode is optional and can be enabled by the
flag -v or --verbose.

The documentation file is only parsed by checkpatch.pl
if the verbose mode is enabled. The verbose mode can
not be used together with the --terse option.

Changes in v7:
- Add color coding support to --list-types option

Changes in v6:
- Allow using verbose mode with --list-types option

Changes in v5:
- Change the reference format to use absolute links.
- Print verbose descriptions only for the first time
  a message type is encountered.

Changes in v4:
- Change the type description format
- Group the message types by usage
- Make handling of --terse with --verbose simpler

Changes in v3:
- Simplify documentation file parsing in checkpatch
- Document a total of 33 message types for checkpatch

Changes in v2:
- Use .rst Field Lists to specify the type descriptions.
- Add a few more type descriptions to documentation.

Dwaipayan Ray (2):
  checkpatch: add verbose mode
  docs: add documentation for checkpatch

 Documentation/dev-tools/checkpatch.rst | 525 +++++++++++++++++++++++++
 Documentation/dev-tools/index.rst      |   1 +
 scripts/checkpatch.pl                  | 133 ++++++-
 3 files changed, 639 insertions(+), 20 deletions(-)
 create mode 100644 Documentation/dev-tools/checkpatch.rst

-- 
2.30.0

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[Linux-kernel-mentees] [PATCH v7 1/2] checkpatch: add verbose mode

[Dwaipayan Ray]

Add a new verbose mode to checkpatch.pl to emit additional verbose
test descriptions. The verbose mode is optional and can be enabled
by the flag -v or --verbose.

The test descriptions are parsed from the checkpatch documentation
file at `Documentation/dev-tools/checkpatch.rst`. The test
descriptions in the docs are kept in a fixed format grouped by
usage. Some examples of this format are:

  **LINE_SPACING**
    Vertical space is wasted given the limited number of lines an
    editor window can display when multiple blank lines are used.

  **MISSING_SIGN_OFF**
    The patch is missing a Signed-off-by line.  A signed-off-by
    line should be added according to Developer's certificate of
    Origin.

To avoid lengthy output, the verbose description is printed only
for the first instance of a particular message type.

The --verbose option cannot be used along with the --terse option.

Verbose mode can be used with the --list-types option.
The --list-types output also supports color coding now.

Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
---
 scripts/checkpatch.pl | 133 +++++++++++++++++++++++++++++++++++-------
 1 file changed, 113 insertions(+), 20 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 9a549b009d2f..7bc3f02fc543 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -23,6 +23,9 @@ my $V = '0.32';
 use Getopt::Long qw(:config no_auto_abbrev);
 
 my $quiet = 0;
+my $verbose = 0;
+my %verbose_messages = ();
+my %verbose_emitted = ();
 my $tree = 1;
 my $chk_signoff = 1;
 my $chk_patch = 1;
@@ -61,6 +64,7 @@ my $spelling_file = "$D/spelling.txt";
 my $codespell = 0;
 my $codespellfile = "/usr/share/codespell/dictionary.txt";
 my $conststructsfile = "$D/const_structs.checkpatch";
+my $docsfile = "$D/../Documentation/dev-tools/checkpatch.rst";
 my $typedefsfile;
 my $color = "auto";
 my $allow_c99_comments = 1; # Can be overridden by --ignore C99_COMMENT_TOLERANCE
@@ -78,6 +82,7 @@ Version: $V
 
 Options:
   -q, --quiet                quiet
+  -v, --verbose              verbose mode
   --no-tree                  run without a kernel tree
   --no-signoff               do not check for 'Signed-off-by' line
   --patch                    treat FILE as patchfile (default)
@@ -158,15 +163,51 @@ sub list_types {
 	my $text = <$script>;
 	close($script);
 
-	my @types = ();
+	my %types = ();
 	# Also catch when type or level is passed through a variable
-	for ($text =~ /(?:(?:\bCHK|\bWARN|\bERROR|&\{\$msg_level})\s*\(|\$msg_type\s*=)\s*"([^"]+)"/g) {
-		push (@types, $_);
+	while ($text =~ /(?:(\bCHK|\bWARN|\bERROR|&\{\$msg_level})\s*\(|\$msg_type\s*=)\s*"([^"]+)"/g) {
+		if (defined($1)) {
+			if (exists($types{$2})) {
+				$types{$2} .= ",$1" if ($types{$2} ne $1);
+			} else {
+				$types{$2} = $1;
+			}
+		} else {
+			$types{$2} = "UNDETERMINED";
+		}
 	}
-	@types = sort(uniq(@types));
+
 	print("#\tMessage type\n\n");
-	foreach my $type (@types) {
+	if ($color) {
+		print(" ( Color coding: ");
+		print(RED . "ERROR" . RESET);
+		print(" | ");
+		print(YELLOW . "WARNING" . RESET);
+		print(" | ");
+		print(GREEN . "CHECK" . RESET);
+		print(" | ");
+		print("Multiple levels / Undetermined");
+		print(" )\n\n");
+	}
+
+	foreach my $type (sort keys %types) {
+		my $orig_type = $type;
+		if ($color) {
+			my $level = $types{$type};
+			if ($level eq "ERROR") {
+				$type = RED . $type . RESET;
+			} elsif ($level eq "WARN") {
+				$type = YELLOW . $type . RESET;
+			} elsif ($level eq "CHK") {
+				$type = GREEN . $type . RESET;
+			}
+		}
 		print(++$count . "\t" . $type . "\n");
+		if ($verbose && exists($verbose_messages{$orig_type})) {
+			my $message = $verbose_messages{$orig_type};
+			$message =~ s/\n/\n\t/g;
+			print("\t" . $message . "\n\n");
+		}
 	}
 
 	exit($exitcode);
@@ -198,6 +239,46 @@ if (-f $conf) {
 	unshift(@ARGV, @conf_args) if @conf_args;
 }
 
+sub load_docs {
+	open(my $docs, '<', "$docsfile")
+	    or warn "$P: Can't read the documentation file $docsfile $!\n";
+
+	my $type = '';
+	my $desc = '';
+	my $in_desc = 0;
+
+	while (<$docs>) {
+		chomp;
+		my $line = $_;
+		$line =~ s/\s+$//;
+
+		if ($line =~ /^\s*\*\*(.+)\*\*$/) {
+			if ($desc ne '') {
+				$verbose_messages{$type} = trim($desc);
+			}
+			$type = $1;
+			$desc = '';
+			$in_desc = 1;
+		} elsif ($in_desc) {
+			if ($line =~ /^(?:\s{4,}|$)/) {
+				$line =~ s/^\s{4}//;
+				$desc .= $line;
+				$desc .= "\n";
+			} else {
+				$verbose_messages{$type} = trim($desc);
+				$type = '';
+				$desc = '';
+				$in_desc = 0;
+			}
+		}
+	}
+
+	if ($desc ne '') {
+		$verbose_messages{$type} = trim($desc);
+	}
+	close($docs);
+}
+
 # Perl's Getopt::Long allows options to take optional arguments after a space.
 # Prevent --color by itself from consuming other arguments
 foreach (@ARGV) {
@@ -208,6 +289,7 @@ foreach (@ARGV) {
 
 GetOptions(
 	'q|quiet+'	=> \$quiet,
+	'v|verbose!'	=> \$verbose,
 	'tree!'		=> \$tree,
 	'signoff!'	=> \$chk_signoff,
 	'patch!'	=> \$chk_patch,
@@ -247,13 +329,27 @@ GetOptions(
 
 help(0) if ($help);
 
+die "$P: --git cannot be used with --file or --fix\n" if ($git && ($file || $fix));
+die "$P: --verbose cannot be used with --terse\n" if ($verbose && $terse);
+
+if ($color =~ /^[01]$/) {
+	$color = !$color;
+} elsif ($color =~ /^always$/i) {
+	$color = 1;
+} elsif ($color =~ /^never$/i) {
+	$color = 0;
+} elsif ($color =~ /^auto$/i) {
+	$color = (-t STDOUT);
+} else {
+	die "$P: Invalid color mode: $color\n";
+}
+
+load_docs() if ($verbose);
 list_types(0) if ($list_types);
 
 $fix = 1 if ($fix_inplace);
 $check_orig = $check;
 
-die "$P: --git cannot be used with --file or --fix\n" if ($git && ($file || $fix));
-
 my $exit = 0;
 
 my $perl_version_ok = 1;
@@ -268,18 +364,6 @@ if ($#ARGV < 0) {
 	push(@ARGV, '-');
 }
 
-if ($color =~ /^[01]$/) {
-	$color = !$color;
-} elsif ($color =~ /^always$/i) {
-	$color = 1;
-} elsif ($color =~ /^never$/i) {
-	$color = 0;
-} elsif ($color =~ /^auto$/i) {
-	$color = (-t STDOUT);
-} else {
-	die "$P: Invalid color mode: $color\n";
-}
-
 # skip TAB size 1 to avoid additional checks on $tabsize - 1
 die "$P: Invalid TAB size: $tabsize\n" if ($tabsize < 2);
 
@@ -2209,7 +2293,16 @@ sub report {
 		splice(@lines, 1, 1);
 		$output = join("\n", @lines);
 	}
-	$output = (split('\n', $output))[0] . "\n" if ($terse);
+
+	if ($terse) {
+		$output = (split('\n', $output))[0] . "\n";
+	}
+
+	if ($verbose && exists($verbose_messages{$type}) &&
+	    !exists($verbose_emitted{$type})) {
+		$output .= $verbose_messages{$type} . "\n\n";
+		$verbose_emitted{$type} = 1;
+	}
 
 	push(our @report, $output);
 
-- 
2.30.0

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[Linux-kernel-mentees] [PATCH v7 2/2] docs: add documentation for checkpatch

[Dwaipayan Ray]

Add documentation for kernel script checkpatch.pl.
This documentation is also parsed by checkpatch to
enable a verbose mode.

The checkpatch message types are grouped by usage. Under
each group the types are described briefly. 34 of such
types are documented.

Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com>
---
 Documentation/dev-tools/checkpatch.rst | 525 +++++++++++++++++++++++++
 Documentation/dev-tools/index.rst      |   1 +
 2 files changed, 526 insertions(+)
 create mode 100644 Documentation/dev-tools/checkpatch.rst

diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
new file mode 100644
index 000000000000..ffb8f66be887
--- /dev/null
+++ b/Documentation/dev-tools/checkpatch.rst
@@ -0,0 +1,525 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+
+==========
+Checkpatch
+==========
+
+This document describes the kernel script checkpatch.pl.
+
+.. Table of Contents
+
+	=== Introduction
+	=== Options
+	=== Message Levels
+	=== Type Descriptions
+
+Introduction
+============
+
+Checkpatch (scripts/checkpatch.pl) is a perl script which checks for trivial
+style violations in patches and optionally corrects them.  Checkpatch can
+also be run on file contexts and without the kernel tree.
+
+Checkpatch is not always right. Your judgement takes precedence over checkpatch
+messages.  If your code looks better with the violations, then its probably
+best left alone.
+
+
+Options
+=======
+
+This section will describe the options checkpatch can be run with.
+
+Usage::
+
+  ./scripts/checkpatch.pl [OPTION]... [FILE]...
+
+Available options:
+
+ - -q,  --quiet
+
+   Enable quiet mode.
+
+ - -v,  --verbose
+   Enable verbose mode.  Additional verbose test descriptions are output
+   so as to provide information on why that particular message is shown.
+
+ - --no-tree
+
+   Run checkpatch without the kernel tree.
+
+ - --no-signoff
+
+   Disable the 'Signed-off-by' line check.  The sign-off is a simple line at
+   the end of the explanation for the patch, which certifies that you wrote it
+   or otherwise have the right to pass it on as an open-source patch.
+
+   Example::
+
+	 Signed-off-by: Random J Developer <random@developer.example.org>
+
+   Setting this flag effectively stops a message for a missing signed-off-by
+   line in a patch context.
+
+ - --patch
+
+   Treat FILE as a patch.  This is the default option and need not be
+   explicitly specified.
+
+ - --emacs
+
+   Set output to emacs compile window format.  This allows emacs users to jump
+   from the error in the compile window directly to the offending line in the
+   patch.
+
+ - --terse
+
+   Output only one line per report.
+
+ - --showfile
+
+   Show the diffed file position instead of the input file position.
+
+ - -g,  --git
+
+   Treat FILE as a single commit or a git revision range.
+
+   Single commit with:
+
+   - <rev>
+   - <rev>^
+   - <rev>~n
+
+   Multiple commits with:
+
+   - <rev1>..<rev2>
+   - <rev1>...<rev2>
+   - <rev>-<count>
+
+ - -f,  --file
+
+   Treat FILE as a regular source file.  This option must be used when running
+   checkpatch on source files in the kernel.
+
+ - --subjective,  --strict
+
+   Enable stricter tests in checkpatch.  By default the tests emitted as CHECK
+   do not activate by default.  Use this flag to activate the CHECK tests.
+
+ - --list-types
+
+   Every message emitted by checkpatch has an associated TYPE.  Add this flag
+   to display all the types in checkpatch.
+
+   Note that when this flag is active, checkpatch does not read the input FILE,
+   and no message is emitted.  Only a list of types in checkpatch is output.
+
+ - --types TYPE(,TYPE2...)
+
+   Only display messages with the given types.
+
+   Example::
+
+     ./scripts/checkpatch.pl mypatch.patch --types EMAIL_SUBJECT,BRACES
+
+ - --ignore TYPE(,TYPE2...)
+
+   Checkpatch will not emit messages for the specified types.
+
+   Example::
+
+     ./scripts/checkpatch.pl mypatch.patch --ignore EMAIL_SUBJECT,BRACES
+
+ - --show-types
+
+   By default checkpatch doesn't display the type associated with the messages.
+   Set this flag to show the message type in the output.
+
+ - --max-line-length=n
+
+   Set the max line length (default 100).  If a line exceeds the specified
+   length, a LONG_LINE message is emitted.
+
+
+   The message level is different for patch and file contexts.  For patches,
+   a WARNING is emitted.  While a milder CHECK is emitted for files.  So for
+   file contexts, the --strict flag must also be enabled.
+
+ - --min-conf-desc-length=n
+
+   Set the Kconfig entry minimum description length, if shorter, warn.
+
+ - --tab-size=n
+
+   Set the number of spaces for tab (default 8).
+
+ - --root=PATH
+
+   PATH to the kernel tree root.
+
+   This option must be specified when invoking checkpatch from outside
+   the kernel root.
+
+ - --no-summary
+
+   Suppress the per file summary.
+
+ - --mailback
+
+   Only produce a report in case of Warnings or Errors.  Milder Checks are
+   excluded from this.
+
+ - --summary-file
+
+   Include the filename in summary.
+
+ - --debug KEY=[0|1]
+
+   Turn on/off debugging of KEY, where KEY is one of 'values', 'possible',
+   'type', and 'attr' (default is all off).
+
+ - --fix
+
+   This is an EXPERIMENTAL feature.  If correctable errors exists, a file
+   <inputfile>.EXPERIMENTAL-checkpatch-fixes is created which has the
+   automatically fixable errors corrected.
+
+ - --fix-inplace
+
+   EXPERIMENTAL - Similar to --fix but input file is overwritten with fixes.
+
+   DO NOT USE this flag unless you are absolutely sure and you have a backup
+   in place.
+
+ - --ignore-perl-version
+
+   Override checking of perl version.  Runtime errors maybe encountered after
+   enabling this flag if the perl version does not meet the minimum specified.
+
+ - --codespell
+
+   Use the codespell dictionary for checking spelling errors.
+
+ - --codespellfile
+
+   Use the specified codespell file.
+   Default is '/usr/share/codespell/dictionary.txt'.
+
+ - --typedefsfile
+
+   Read additional types from this file.
+
+ - --color[=WHEN]
+
+   Use colors 'always', 'never', or only when output is a terminal ('auto').
+   Default is 'auto'.
+
+ - --kconfig-prefix=WORD
+
+   Use WORD as a prefix for Kconfig symbols (default is `CONFIG_`).
+
+ - -h, --help, --version
+
+   Display the help text.
+
+Message Levels
+==============
+
+Messages in checkpatch are divided into three levels. The levels of messages
+in checkpatch denote the severity of the error. They are:
+
+ - ERROR
+
+   This is the most strict level.  Messages of type ERROR must be taken
+   seriously as they denote things that are very likely to be wrong.
+
+ - WARNING
+
+   This is the next stricter level.  Messages of type WARNING requires a
+   more careful review.  But it is milder than an ERROR.
+
+ - CHECK
+
+   This is the mildest level.  These are things which may require some thought.
+
+Type Descriptions
+=================
+
+This section contains a description of all the message types in checkpatch.
+
+.. Types in this section are also parsed by checkpatch.
+.. The types are grouped into subsections based on use.
+
+
+Allocation style
+----------------
+
+  **ALLOC_ARRAY_ARGS**
+    The first argument for kcalloc or kmalloc_array should be the
+    number of elements.  sizeof() as the first argument is generally
+    wrong.
+    See: https://www.kernel.org/doc/html/latest/core-api/memory-allocation.html
+
+  **ALLOC_SIZEOF_STRUCT**
+    The allocation style is bad.  In general for family of
+    allocation functions using sizeof() to get memory size,
+    constructs like::
+
+      p = alloc(sizeof(struct foo), ...)
+
+    should be::
+
+      p = alloc(sizeof(*p), ...)
+
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#allocating-memory
+
+  **ALLOC_WITH_MULTIPLY**
+    Prefer kmalloc_array/kcalloc over kmalloc/kzalloc with a
+    sizeof multiply.
+    See: https://www.kernel.org/doc/html/latest/core-api/memory-allocation.html
+
+
+API usage
+---------
+
+  **ARCH_DEFINES**
+    Architecture specific defines should be avoided wherever
+    possible.
+
+  **ARCH_INCLUDE_LINUX**
+    Whenever asm/file.h is included and linux/file.h exists, a
+    conversion can be made when linux/file.h includes asm/file.h.
+    However this is not always the case (See signal.h).
+    This message type is emitted only for includes from arch/.
+
+  **ARRAY_SIZE**
+    The ARRAY_SIZE(foo) macro should be preferred over
+    sizeof(foo)/sizeof(foo[0]) for finding number of elements in an
+    array.
+
+    The macro is defined in include/linux/kernel.h::
+
+      #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+  **AVOID_BUG**
+    BUG() or BUG_ON() should be avoided totally.
+    Use WARN() and WARN_ON() instead, and handle the "impossible"
+    error condition as gracefully as possible.
+    See: https://www.kernel.org/doc/html/latest/process/deprecated.html#bug-and-bug-on
+
+  **AVOID_EXTERNS**
+    Function prototypes don't need to be declared extern in .h
+    files.  It's assumed by the compiler and is unnecessary.
+
+  **AVOID_L_PREFIX**
+    Local symbol names that are prefixed with `.L` should be avoided,
+    as this has special meaning for the assembler; a symbol entry will
+    not be emitted into the symbol table.  This can prevent `objtool`
+    from generating correct unwind info.
+
+    Symbols with STB_LOCAL binding may still be used, and `.L` prefixed
+    local symbol names are still generally usable within a function,
+    but `.L` prefixed local symbol names should not be used to denote
+    the beginning or end of code regions via
+    `SYM_CODE_START_LOCAL`/`SYM_CODE_END`
+
+  **BIT_MACRO**
+    Defines like: 1 << <digit> could be BIT(digit).
+    The BIT() macro is defined in include/linux/bitops.h::
+
+      #define BIT(nr)         (1UL << (nr))
+
+  **CONSIDER_KSTRTO**
+    The simple_strtol(), simple_strtoll(), simple_strtoul(), and
+    simple_strtoull() functions explicitly ignore overflows, which
+    may lead to unexpected results in callers.  The respective kstrtol(),
+    kstrtoll(), kstrtoul(), and kstrtoull() functions tend to be the
+    correct replacements.
+    See: https://www.kernel.org/doc/html/latest/process/deprecated.html#simple-strtol-simple-strtoll-simple-strtoul-simple-strtoull
+
+
+Comment style
+-------------
+
+  **BLOCK_COMMENT_STYLE**
+    The comment style is incorrect.  The preferred style for multi-
+    line comments is::
+
+      /*
+      * This is the preferred style
+      * for multi line comments.
+      */
+
+    The networking comment style is a bit different, with the first line
+    not empty like the former::
+
+      /* This is the preferred comment style
+      * for files in net/ and drivers/net/
+      */
+
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#commenting
+
+  **C99_COMMENTS**
+    C99 style single line comments (//) should not be used.
+    Prefer the block comment style instead.
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#commenting
+
+
+
+Commit message
+--------------
+
+  **BAD_SIGN_OFF**
+    The signed-off-by line does not fall in line with the standards
+    specified by the community.
+    See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#developer-s-certificate-of-origin-1-1
+
+  **BAD_STABLE_ADDRESS_STYLE**
+    The email format for stable is incorrect.
+    Some valid options for stable address are::
+
+      1. stable@vger.kernel.org
+      2. stable@kernel.org
+
+    For adding version info, the following comment style should be used::
+
+      stable@vger.kernel.org # version info
+
+  **COMMIT_COMMENT_SYMBOL**
+    Commit log lines starting with a '#' are ignored by git as
+    comments.  To solve this problem addition of a single space
+    infront of the log line is enough.
+
+  **COMMIT_MESSAGE**
+    The patch is missing a commit description.  A brief
+    description of the changes made by the patch should be added.
+    See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#describe-your-changes
+
+  **MISSING_SIGN_OFF**
+    The patch is missing a Signed-off-by line.  A signed-off-by
+    line should be added according to Developer's certificate of
+    Origin.
+    See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
+
+  **NO_AUTHOR_SIGN_OFF**
+    The author of the patch has not signed off the patch.  It is
+    required that a simple sign off line should be present at the
+    end of explanation of the patch to denote that the author has
+    written it or otherwise has the rights to pass it on as an open
+    source patch.
+    See: https://www.kernel.org/doc/html/latest/process/submitting-patches.html#sign-your-work-the-developer-s-certificate-of-origin
+
+
+Comparison style
+----------------
+
+  **ASSIGN_IN_IF**
+    Do not use assignments in if condition.
+    Example::
+
+      if ((foo = bar(...)) < BAZ) {
+
+    should be written as::
+
+      foo = bar(...);
+      if (foo < BAZ) {
+
+  **BOOL_COMPARISON**
+    Comparisons of A to true and false are better written
+    as A and !A.
+    See: https://lore.kernel.org/lkml/1365563834.27174.12.camel@joe-AO722/
+
+  **COMPARISON_TO_NULL**
+    Comparisons to NULL in the form (foo == NULL) or (foo != NULL)
+    are better written as (!foo) and (foo).
+
+  **CONSTANT_COMPARISON**
+    Comparisons with a constant or upper case identifier on the left
+    side of the test should be avoided.
+
+
+Spacing and Brackets
+--------------------
+
+  **ASSIGNMENT_CONTINUATIONS**
+    Assignment operators should not be written at the start of a
+    line but should follow the operand at the previous line.
+
+  **BRACES**
+    The placement of braces is stylistically incorrect.
+    The preferred way is to put the opening brace last on the line,
+    and put the closing brace first::
+
+      if (x is true) {
+        we do y
+      }
+
+    This applies for all non-functional blocks.
+    However, there is one special case, namely functions: they have the
+    opening brace at the beginning of the next line, thus::
+
+      int function(int x)
+      {
+        body of function
+      }
+
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#placing-braces-and-spaces
+
+  **BRACKET_SPACE**
+    Whitespace before opening bracket '[' is prohibited.
+    There are some exceptions:
+
+    1. With a type on the left::
+
+        ;int [] a;
+
+    2. At the beginning of a line for slice initialisers::
+
+        [0...10] = 5,
+
+    3. Inside a curly brace::
+
+        = { [0...10] = 5 }
+
+  **CODE_INDENT**
+    Code indent should use tabs instead of spaces.
+    Outside of comments, documentation and Kconfig,
+    spaces are never used for indentation.
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#indentation
+
+  **CONCATENATED_STRING**
+    Concatenated elements should have a space in between.
+    Example::
+
+      printk(KERN_INFO"bar");
+
+    should be::
+
+      printk(KERN_INFO "bar");
+
+  **LINE_SPACING**
+    Vertical space is wasted given the limited number of lines an
+    editor window can display when multiple blank lines are used.
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#spaces
+
+  **SPACING**
+    Whitespace style used in the kernel sources is described in kernel docs.
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#spaces
+
+  **TRAILING_WHITESPACE**
+    Trailing whitespace should always be removed.
+    Some editors highlight the trailing whitespace and cause visual
+    distractions when editing files.
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#spaces
+
+
+Others
+------
+
+  **CAMELCASE**
+    Avoid CamelCase Identifiers.
+    See: https://www.kernel.org/doc/html/latest/process/coding-style.html#naming
+
+  **CONFIG_DESCRIPTION**
+    Kconfig symbols should have a help text which fully describes
+    it.
diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst
index 1b1cf4f5c9d9..43d28998118b 100644
--- a/Documentation/dev-tools/index.rst
+++ b/Documentation/dev-tools/index.rst
@@ -14,6 +14,7 @@ whole; patches welcome!
 .. toctree::
    :maxdepth: 2
 
+   checkpatch
    coccinelle
    sparse
    kcov
-- 
2.30.0

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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Joe Perches]

On Mon, 2021-02-22 at 13:22 +0530, Dwaipayan Ray wrote:
> Add a new verbose mode to checkpatch. The verbose test
> descriptions are read from the checkpatch documentation
> file at `Documentation/dev-tools/checkpatch.rst`.
> 
> The verbose mode is optional and can be enabled by the
> flag -v or --verbose.
> 
> The documentation file is only parsed by checkpatch.pl
> if the verbose mode is enabled. The verbose mode can
> not be used together with the --terse option.

I don't have any real objection to this patch set, but as this
might be added to the Documentation tree and in .rst format,
perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
some opinion.

Also I do not want to be a maintainer of this .rst file and
likely neither Jon nor Mauro would either.  Perhaps you?

Ideally, the patch order would be reversed so the .rst file
is added first, then checkpatch updated to use it.

And _a lot_ more types and descriptive content should be added.

> 
> Changes in v7:
> - Add color coding support to --list-types option
> 
> Changes in v6:
> - Allow using verbose mode with --list-types option
> 
> Changes in v5:
> - Change the reference format to use absolute links.
> - Print verbose descriptions only for the first time
>   a message type is encountered.
> 
> Changes in v4:
> - Change the type description format
> - Group the message types by usage
> - Make handling of --terse with --verbose simpler
> 
> Changes in v3:
> - Simplify documentation file parsing in checkpatch
> - Document a total of 33 message types for checkpatch
> 
> Changes in v2:
> - Use .rst Field Lists to specify the type descriptions.
> - Add a few more type descriptions to documentation.
> 
> Dwaipayan Ray (2):
>   checkpatch: add verbose mode
>   docs: add documentation for checkpatch
> 
>  Documentation/dev-tools/checkpatch.rst | 525 +++++++++++++++++++++++++
>  Documentation/dev-tools/index.rst      |   1 +
>  scripts/checkpatch.pl                  | 133 ++++++-
>  3 files changed, 639 insertions(+), 20 deletions(-)
>  create mode 100644 Documentation/dev-tools/checkpatch.rst
> 


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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Dwaipayan Ray]

On Thu, Feb 25, 2021 at 11:03 PM Joe Perches <joe@perches.com> wrote:
>
> On Mon, 2021-02-22 at 13:22 +0530, Dwaipayan Ray wrote:
> > Add a new verbose mode to checkpatch. The verbose test
> > descriptions are read from the checkpatch documentation
> > file at `Documentation/dev-tools/checkpatch.rst`.
> >
> > The verbose mode is optional and can be enabled by the
> > flag -v or --verbose.
> >
> > The documentation file is only parsed by checkpatch.pl
> > if the verbose mode is enabled. The verbose mode can
> > not be used together with the --terse option.
>
> I don't have any real objection to this patch set, but as this
> might be added to the Documentation tree and in .rst format,
> perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
> some opinion.
>
> Also I do not want to be a maintainer of this .rst file and
> likely neither Jon nor Mauro would either.  Perhaps you?
>

I could take it up if everybody is okay with it!

> Ideally, the patch order would be reversed so the .rst file
> is added first, then checkpatch updated to use it.
>

Sure, if Jonathan or Mauro has no objections to it, I will be happy
to resend it so that it can be picked up properly.

> And _a lot_ more types and descriptive content should be added.

Yes that's for sure. If this makes it I will try to get all of the
other types in.
And if Lukas agrees, a little help from my fellow kernel mentees will
be nice as well!

With warm regards,
Dwaipayan.

> >
> > Changes in v7:
> > - Add color coding support to --list-types option
> >
> > Changes in v6:
> > - Allow using verbose mode with --list-types option
> >
> > Changes in v5:
> > - Change the reference format to use absolute links.
> > - Print verbose descriptions only for the first time
> >   a message type is encountered.
> >
> > Changes in v4:
> > - Change the type description format
> > - Group the message types by usage
> > - Make handling of --terse with --verbose simpler
> >
> > Changes in v3:
> > - Simplify documentation file parsing in checkpatch
> > - Document a total of 33 message types for checkpatch
> >
> > Changes in v2:
> > - Use .rst Field Lists to specify the type descriptions.
> > - Add a few more type descriptions to documentation.
> >
> > Dwaipayan Ray (2):
> >   checkpatch: add verbose mode
> >   docs: add documentation for checkpatch
> >
> >  Documentation/dev-tools/checkpatch.rst | 525 +++++++++++++++++++++++++
> >  Documentation/dev-tools/index.rst      |   1 +
> >  scripts/checkpatch.pl                  | 133 ++++++-
> >  3 files changed, 639 insertions(+), 20 deletions(-)
> >  create mode 100644 Documentation/dev-tools/checkpatch.rst
> >
>
>
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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Mauro Carvalho Chehab]

Em Thu, 25 Feb 2021 23:38:03 +0530
Dwaipayan Ray <dwaipayanray1@gmail.com> escreveu:

> On Thu, Feb 25, 2021 at 11:03 PM Joe Perches <joe@perches.com> wrote:
> >
> > On Mon, 2021-02-22 at 13:22 +0530, Dwaipayan Ray wrote:  
> > > Add a new verbose mode to checkpatch. The verbose test
> > > descriptions are read from the checkpatch documentation
> > > file at `Documentation/dev-tools/checkpatch.rst`.
> > >
> > > The verbose mode is optional and can be enabled by the
> > > flag -v or --verbose.
> > >
> > > The documentation file is only parsed by checkpatch.pl
> > > if the verbose mode is enabled. The verbose mode can
> > > not be used together with the --terse option.  
> >
> > I don't have any real objection to this patch set, but as this
> > might be added to the Documentation tree and in .rst format,
> > perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
> > some opinion.
> >
> > Also I do not want to be a maintainer of this .rst file and
> > likely neither Jon nor Mauro would either.  Perhaps you?
> >  
> 
> I could take it up if everybody is okay with it!
> 
> > Ideally, the patch order would be reversed so the .rst file
> > is added first, then checkpatch updated to use it.
> >  
> 
> Sure, if Jonathan or Mauro has no objections to it, I will be happy
> to resend it so that it can be picked up properly.

I don't have any objections, provided that I won't be maintaining
it :-)

-

Just my two cents:

IMO, maintaining this on a separate file can be a maintenance nightmare, 
as this is the kind of thing that can become obsolete real soon.

One alternative would be to use Pod::Usage module, just like
this script does:

	scripts/get_abi.pl

with something similar to that, calling

	$ checkpatch --man 

Could generate a man-page style with all options, while:

	$ checkpatch --help

would print the current help page.

Yet, this would generate more work for Joe, as, for every new
type, the corresponding help text would be needed.

Thanks,
Mauro
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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Joe Perches]

On Thu, 2021-02-25 at 21:55 +0100, Mauro Carvalho Chehab wrote:
> Em Thu, 25 Feb 2021 23:38:03 +0530
> Dwaipayan Ray <dwaipayanray1@gmail.com> escreveu:
> 
> > On Thu, Feb 25, 2021 at 11:03 PM Joe Perches <joe@perches.com> wrote:
> > > 
> > > On Mon, 2021-02-22 at 13:22 +0530, Dwaipayan Ray wrote:  
> > > > Add a new verbose mode to checkpatch. The verbose test
> > > > descriptions are read from the checkpatch documentation
> > > > file at `Documentation/dev-tools/checkpatch.rst`.
> > > > 
> > > > The verbose mode is optional and can be enabled by the
> > > > flag -v or --verbose.
> > > > 
> > > > The documentation file is only parsed by checkpatch.pl
> > > > if the verbose mode is enabled. The verbose mode can
> > > > not be used together with the --terse option.  
> > > 
> > > I don't have any real objection to this patch set, but as this
> > > might be added to the Documentation tree and in .rst format,
> > > perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
> > > some opinion.
> > > 
> > > Also I do not want to be a maintainer of this .rst file and
> > > likely neither Jon nor Mauro would either.  Perhaps you?
> > >  
> > > 
> > 
> > I could take it up if everybody is okay with it!
> > 
> > > Ideally, the patch order would be reversed so the .rst file
> > > is added first, then checkpatch updated to use it.
> > >  
> > > 
> > 
> > Sure, if Jonathan or Mauro has no objections to it, I will be happy
> > to resend it so that it can be picked up properly.
> 
> I don't have any objections, provided that I won't be maintaining
> it :-)
> 
> -
> 
> Just my two cents:
> 
> IMO, maintaining this on a separate file can be a maintenance nightmare, 
> as this is the kind of thing that can become obsolete real soon.
> 
> One alternative would be to use Pod::Usage module, just like
> this script does:
> 
> 	scripts/get_abi.pl
> 
> with something similar to that, calling
> 
> 	$ checkpatch --man 
> 
> Could generate a man-page style with all options, while:
> 
> 	$ checkpatch --help
> 
> would print the current help page.
> 
> Yet, this would generate more work for Joe, as, for every new
> type, the corresponding help text would be needed.

Does this get integrated into the .rst output?

I see:
Documentation/Makefile:$(shell $(srctree)/scripts/get_abi.pl validate --dir $(srctree)/Documentation/ABI)

But no obvious mechanism that emits .rst files for Pod::Usage

And no, I'm not much interested in maintaining those docs either.


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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Jonathan Corbet]

Dwaipayan Ray <dwaipayanray1@gmail.com> writes:

> On Thu, Feb 25, 2021 at 11:03 PM Joe Perches <joe@perches.com> wrote:
>> I don't have any real objection to this patch set, but as this
>> might be added to the Documentation tree and in .rst format,
>> perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
>> some opinion.
>>
>> Also I do not want to be a maintainer of this .rst file and
>> likely neither Jon nor Mauro would either.  Perhaps you?
>>
>
> I could take it up if everybody is okay with it!
>
>> Ideally, the patch order would be reversed so the .rst file
>> is added first, then checkpatch updated to use it.
>>
>
> Sure, if Jonathan or Mauro has no objections to it, I will be happy
> to resend it so that it can be picked up properly.

So I haven't been copied on this for a while.  Looking in the archives,
I see that you have a manual table of contents at the top of the
document; you could take that out and let Sphinx generate it (and keep
it current!) for you.

Either way, though, if you want to merge this via some other path, it's
OK by me:

Acked-by: Jonathan Corbet <corbet@lwn.net>

Thanks,

jon
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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Dwaipayan Ray]

On Fri, Feb 26, 2021 at 2:46 AM Jonathan Corbet <corbet@lwn.net> wrote:
>
> Dwaipayan Ray <dwaipayanray1@gmail.com> writes:
>
> > On Thu, Feb 25, 2021 at 11:03 PM Joe Perches <joe@perches.com> wrote:
> >> I don't have any real objection to this patch set, but as this
> >> might be added to the Documentation tree and in .rst format,
> >> perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
> >> some opinion.
> >>
> >> Also I do not want to be a maintainer of this .rst file and
> >> likely neither Jon nor Mauro would either.  Perhaps you?
> >>
> >
> > I could take it up if everybody is okay with it!
> >
> >> Ideally, the patch order would be reversed so the .rst file
> >> is added first, then checkpatch updated to use it.
> >>
> >
> > Sure, if Jonathan or Mauro has no objections to it, I will be happy
> > to resend it so that it can be picked up properly.
>
> So I haven't been copied on this for a while.  Looking in the archives,
> I see that you have a manual table of contents at the top of the
> document; you could take that out and let Sphinx generate it (and keep
> it current!) for you.
>

Sure that sounds nice.
I will modify the series and send the v8 in so that you can pick it up
from there. That shall include the MAINTAINERS patch sent by Lukas
as well.

> Either way, though, if you want to merge this via some other path, it's
> OK by me:
>
> Acked-by: Jonathan Corbet <corbet@lwn.net>
>
Thanks for the ack!

Regards,
Dwaipayan.

> Thanks,
>
> jon
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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Lukas Bulwahn]

On Thu, Feb 25, 2021 at 7:08 PM Dwaipayan Ray <dwaipayanray1@gmail.com> wrote:
>
> On Thu, Feb 25, 2021 at 11:03 PM Joe Perches <joe@perches.com> wrote:
> >
> > On Mon, 2021-02-22 at 13:22 +0530, Dwaipayan Ray wrote:
> > > Add a new verbose mode to checkpatch. The verbose test
> > > descriptions are read from the checkpatch documentation
> > > file at `Documentation/dev-tools/checkpatch.rst`.
> > >
> > > The verbose mode is optional and can be enabled by the
> > > flag -v or --verbose.
> > >
> > > The documentation file is only parsed by checkpatch.pl
> > > if the verbose mode is enabled. The verbose mode can
> > > not be used together with the --terse option.
> >
> > I don't have any real objection to this patch set, but as this
> > might be added to the Documentation tree and in .rst format,
> > perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
> > some opinion.
> >
> > Also I do not want to be a maintainer of this .rst file and
> > likely neither Jon nor Mauro would either.  Perhaps you?
> >
>
> I could take it up if everybody is okay with it!
>

And as I set Dwaipayan on this task on documenting checkpatch, I will
assist in maintaining this file as well. I will also pull some strings
to increase chances that Dwaipayan becomes a longer-term member in
this community and on this maintainer task.

> > Ideally, the patch order would be reversed so the .rst file
> > is added first, then checkpatch updated to use it.
> >
>
> Sure, if Jonathan or Mauro has no objections to it, I will be happy
> to resend it so that it can be picked up properly.
>
> > And _a lot_ more types and descriptive content should be added.
>
> Yes that's for sure. If this makes it I will try to get all of the
> other types in.

I agree as well, probably a critical mass for inclusion is that we
have at least 25% (so roughly 50 rules) documented.

> And if Lukas agrees, a little help from my fellow kernel mentees will
> be nice as well!
>

Completely agree. I will recruit new mentees and go through the
exercises with them, until they are ready to send proper patches to
checkpatch.rst. As the designated maintainer of that file, you will be
busy reviewing, consolidating that content and pushing back if it is
not good enough for inclusion (so just as in the typical "good cop-bad
cop" game: I will motivate and help them to submit, you make sure you
get good content).

Lukas
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Re: [PATCH v7 0/2] checkpatch: add verbose mode

[Dwaipayan Ray]

On Fri, Feb 26, 2021 at 11:29 AM Lukas Bulwahn <lukas.bulwahn@gmail.com> wrote:
>
> On Thu, Feb 25, 2021 at 7:08 PM Dwaipayan Ray <dwaipayanray1@gmail.com> wrote:
> >
> > On Thu, Feb 25, 2021 at 11:03 PM Joe Perches <joe@perches.com> wrote:
> > >
> > > On Mon, 2021-02-22 at 13:22 +0530, Dwaipayan Ray wrote:
> > > > Add a new verbose mode to checkpatch. The verbose test
> > > > descriptions are read from the checkpatch documentation
> > > > file at `Documentation/dev-tools/checkpatch.rst`.
> > > >
> > > > The verbose mode is optional and can be enabled by the
> > > > flag -v or --verbose.
> > > >
> > > > The documentation file is only parsed by checkpatch.pl
> > > > if the verbose mode is enabled. The verbose mode can
> > > > not be used together with the --terse option.
> > >
> > > I don't have any real objection to this patch set, but as this
> > > might be added to the Documentation tree and in .rst format,
> > > perhaps Jonathan Corbet and/or Mauro Carvalho Chehab might have
> > > some opinion.
> > >
> > > Also I do not want to be a maintainer of this .rst file and
> > > likely neither Jon nor Mauro would either.  Perhaps you?
> > >
> >
> > I could take it up if everybody is okay with it!
> >
>
> And as I set Dwaipayan on this task on documenting checkpatch, I will
> assist in maintaining this file as well. I will also pull some strings
> to increase chances that Dwaipayan becomes a longer-term member in
> this community and on this maintainer task.
>
Sounds nice to me! I would definitely love to remain as a active
member even after the mentorship period ends. So I think this is a good
start :)

> > > Ideally, the patch order would be reversed so the .rst file
> > > is added first, then checkpatch updated to use it.
> > >
> >
> > Sure, if Jonathan or Mauro has no objections to it, I will be happy
> > to resend it so that it can be picked up properly.
> >
> > > And _a lot_ more types and descriptive content should be added.
> >
> > Yes that's for sure. If this makes it I will try to get all of the
> > other types in.
>
> I agree as well, probably a critical mass for inclusion is that we
> have at least 25% (so roughly 50 rules) documented.
>
> > And if Lukas agrees, a little help from my fellow kernel mentees will
> > be nice as well!
> >
>
> Completely agree. I will recruit new mentees and go through the
> exercises with them, until they are ready to send proper patches to
> checkpatch.rst. As the designated maintainer of that file, you will be
> busy reviewing, consolidating that content and pushing back if it is
> not good enough for inclusion (so just as in the typical "good cop-bad
> cop" game: I will motivate and help them to submit, you make sure you
> get good content).
>
That is a nice plan! Certainly looking forward to it.

Thanks & Regards,
Dwaipayan.
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