scripts/checkpatch.pl: some improvements to reduce false positives

- camelcase is OK for printk inttypes.h;
- strncpy is OK;
- accept up to 120 chars on lines without warnings;
- stop complaining about "BACKTRACE=" strings split on multiple lines;
- remove PREFER_DEFINED_ATTRIBUTE_MACRO, as this is kernel-specific;
- remove MACRO_ARG_REUSE, as this applies mostly to multithreading;
- don't warn on using do{} while(0) with single line statements;

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 7ebc4ad1a73461c301f23975d962af2befc59fe2..1c8afbce6c77ac0020a4baab0ffd117c4d749d39 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -55,7 +55,7 @@ my %ignore_type = ();
 my @ignore = ();
 my $help = 0;
 my $configuration_file = ".checkpatch.conf";
-my $max_line_length = 100;
+my $max_line_length = 120;
 my $ignore_perl_version = 0;
 my $minimum_perl_version = 5.10.0;
 my $min_conf_desc_length = 4;
@@ -5636,12 +5636,10 @@ sub process {
 #CamelCase
                        if ($var !~ /^$Constant$/ &&
                            $var =~ /[A-Z][a-z]|[a-z][A-Z]/ &&
+#Ignore inttypes.h macros
+                           $var !~ /^_*PRI(b|d|i|o|u|x)(8|16|32|64|PTR)/ &&
 #Ignore some autogenerated defines and enum values
                            $var !~ /^(?:[A-Z]+_){1,5}[A-Z]{1,3}[a-z]/ &&
-#Ignore Page<foo> variants
-                           $var !~ /^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
-#Ignore ETHTOOL_LINK_MODE_<foo> variants
-                           $var !~ /^ETHTOOL_LINK_MODE_/ &&
 #Ignore SI style variants like nS, mV and dB
 #(ie: max_uV, regulator_min_uA_show, RANGE_mA_VALUE)
                            $var !~ /^(?:[a-z0-9_]*|[A-Z0-9_]*)?_?[a-z][A-Z](?:_[a-z0-9_]+|_[A-Z0-9_]+)?$/ &&
@@ -5825,10 +5823,6 @@ sub process {
                                $tmp_stmt =~ s/\#+\s*$arg\b//g;
                                $tmp_stmt =~ s/\b$arg\s*\#\#//g;
                                my $use_cnt = () = $tmp_stmt =~ /\b$arg\b/g;
-                               if ($use_cnt > 1) {
-                                       CHK("MACRO_ARG_REUSE",
-                                           "Macro argument reuse '$arg' - possible side-effects?\n" . "$herectx");
-                                   }
 # check if any macro arguments may have other precedence issues
                                if ($tmp_stmt =~ m/($Operators)?\s*\b$arg\b\s*($Operators)?/m &&
                                    ((defined($1) && $1 ne ',') ||
@@ -5894,11 +5888,6 @@ sub process {
                                my $cnt = statement_rawlines($ctx);
                                my $herectx = get_stat_here($linenr, $cnt, $here);
 
-                               if (($stmts =~ tr/;/;/) == 1 &&
-                                   $stmts !~ /^\s*(if|while|for|switch)\b/) {
-                                       WARN("SINGLE_STATEMENT_DO_WHILE_MACRO",
-                                            "Single statement macros should not use a do {} while (0) loop\n" . "$herectx");
-                               }
                                if (defined $semis && $semis ne "") {
                                        WARN("DO_WHILE_MACRO_WITH_TRAILING_SEMICOLON",
                                             "do {} while (0) macros should not be semicolon terminated\n" . "$herectx");
@@ -6058,11 +6047,10 @@ sub process {
 
 # Check for user-visible strings broken across lines, which breaks the ability
 # to grep for the string.  Make exceptions when the previous string ends in a
-# newline (multiple lines in one string constant) or '\t', '\r', ';', or '{'
-# (common in inline assembly) or is a octal \123 or hexadecimal \xaf value
+# newline (multiple lines in one string constant) or '\t', '\r' or '='
                if ($line =~ /^\+\s*$String/ &&
                    $prevline =~ /"\s*$/ &&
-                   $prevrawline !~ /(?:\\(?:[ntr]|[0-7]{1,3}|x[0-9a-fA-F]{1,2})|;\s*|\{\s*)"\s*$/) {
+                   $prevrawline !~ /(?:\\(?:[ntr])|=)"\s*$/) {
                        if (WARN("SPLIT_STRING",
                                 "quoted string split across lines\n" . $hereprev) &&
                                     $fix &&
@@ -6508,71 +6496,6 @@ sub process {
                        }
                }
 
-# Check for compiler attributes
-               if ($realfile !~ m@\binclude/uapi/@ &&
-                   $rawline =~ /\b__attribute__\s*\(\s*($balanced_parens)\s*\)/) {
-                       my $attr = $1;
-                       $attr =~ s/\s*\(\s*(.*)\)\s*/$1/;
-
-                       my %attr_list = (
-                               "alias"                         => "__alias",
-                               "aligned"                       => "__aligned",
-                               "always_inline"                 => "__always_inline",
-                               "assume_aligned"                => "__assume_aligned",
-                               "cold"                          => "__cold",
-                               "const"                         => "__attribute_const__",
-                               "copy"                          => "__copy",
-                               "designated_init"               => "__designated_init",
-                               "externally_visible"            => "__visible",
-                               "format"                        => "printf|scanf",
-                               "gnu_inline"                    => "__gnu_inline",
-                               "malloc"                        => "__malloc",
-                               "mode"                          => "__mode",
-                               "no_caller_saved_registers"     => "__no_caller_saved_registers",
-                               "noclone"                       => "__noclone",
-                               "noinline"                      => "noinline",
-                               "nonstring"                     => "__nonstring",
-                               "noreturn"                      => "__noreturn",
-                               "packed"                        => "__packed",
-                               "pure"                          => "__pure",
-                               "section"                       => "__section",
-                               "used"                          => "__used",
-                               "weak"                          => "__weak"
-                       );
-
-                       while ($attr =~ /\s*(\w+)\s*(${balanced_parens})?/g) {
-                               my $orig_attr = $1;
-                               my $params = '';
-                               $params = $2 if defined($2);
-                               my $curr_attr = $orig_attr;
-                               $curr_attr =~ s/^[\s_]+|[\s_]+$//g;
-                               if (exists($attr_list{$curr_attr})) {
-                                       my $new = $attr_list{$curr_attr};
-                                       if ($curr_attr eq "format" && $params) {
-                                               $params =~ /^\s*\(\s*(\w+)\s*,\s*(.*)/;
-                                               $new = "__$1\($2";
-                                       } else {
-                                               $new = "$new$params";
-                                       }
-                                       if (WARN("PREFER_DEFINED_ATTRIBUTE_MACRO",
-                                                "Prefer $new over __attribute__(($orig_attr$params))\n" . $herecurr) &&
-                                           $fix) {
-                                               my $remove = "\Q$orig_attr\E" . '\s*' . "\Q$params\E" . '(?:\s*,\s*)?';
-                                               $fixed[$fixlinenr] =~ s/$remove//;
-                                               $fixed[$fixlinenr] =~ s/\b__attribute__/$new __attribute__/;
-                                               $fixed[$fixlinenr] =~ s/\}\Q$new\E/} $new/;
-                                               $fixed[$fixlinenr] =~ s/ __attribute__\s*\(\s*\(\s*\)\s*\)//;
-                                       }
-                               }
-                       }
-
-                       # Check for __attribute__ unused, prefer __always_unused or __maybe_unused
-                       if ($attr =~ /^_*unused/) {
-                               WARN("PREFER_DEFINED_ATTRIBUTE_MACRO",
-                                    "__always_unused or __maybe_unused is preferred over __attribute__((__unused__))\n" . $herecurr);
-                       }
-               }
-
 # Check for __attribute__ weak, or __weak declarations (may have link issues)
                if ($perl_version_ok &&
                    $line =~ /(?:$Declare|$DeclareMisordered)\s*$Ident\s*$balanced_parens\s*(?:$Attribute)?\s*;/ &&
@@ -6752,22 +6675,10 @@ sub process {
 #                      }
 #              }
 
-# strcpy uses that should likely be strscpy
+# strcpy should be avoided
                if ($line =~ /\bstrcpy\s*\(/) {
                        WARN("STRCPY",
-                            "Prefer strscpy over strcpy - see: https://github.com/KSPP/linux/issues/88\n" . $herecurr);
-               }
-
-# strlcpy uses that should likely be strscpy
-               if ($line =~ /\bstrlcpy\s*\(/) {
-                       WARN("STRLCPY",
-                            "Prefer strscpy over strlcpy - see: https://github.com/KSPP/linux/issues/89\n" . $herecurr);
-               }
-
-# strncpy uses that should likely be strscpy or strscpy_pad
-               if ($line =~ /\bstrncpy\s*\(/) {
-                       WARN("STRNCPY",
-                            "Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90\n" . $herecurr);
+                            "Please avoid strcpy\n" . $herecurr);
                }
 
 # ethtool_sprintf uses that should likely be ethtool_puts