checkpatch.pl

				$off += length($elements[$n]);

				# Pick up the preceding and succeeding characters.
				my $ca = substr($opline, 0, $off);
				my $cc = '';
				if (length($opline) >= ($off + length($elements[$n + 1]))) {
					$cc = substr($opline, $off + length($elements[$n + 1]));
				}
				my $cb = "$ca$;$cc";

				my $a = '';
				$a = 'V' if ($elements[$n] ne '');
				$a = 'W' if ($elements[$n] =~ /\s$/);
				$a = 'C' if ($elements[$n] =~ /$;$/);
				$a = 'B' if ($elements[$n] =~ /(\[|\()$/);
				$a = 'O' if ($elements[$n] eq '');
				$a = 'E' if ($ca =~ /^\s*$/);

				my $op = $elements[$n + 1];

				my $c = '';
				if (defined $elements[$n + 2]) {
					$c = 'V' if ($elements[$n + 2] ne '');
					$c = 'W' if ($elements[$n + 2] =~ /^\s/);
					$c = 'C' if ($elements[$n + 2] =~ /^$;/);
					$c = 'B' if ($elements[$n + 2] =~ /^(\)|\]|;)/);
					$c = 'O' if ($elements[$n + 2] eq '');
					$c = 'E' if ($elements[$n + 2] =~ /^\s*\\$/);
				} else {
					$c = 'E';
				}

				my $ctx = "${a}x${c}";

				my $at = "(ctx:$ctx)";

				my $ptr = substr($blank, 0, $off) . "^";
				my $hereptr = "$hereline$ptr\n";

				# Pull out the value of this operator.
				my $op_type = substr($curr_values, $off + 1, 1);

				# Get the full operator variant.
				my $opv = $op . substr($curr_vars, $off, 1);

				# Ignore operators passed as parameters.
				if ($op_type ne 'V' &&
				    $ca =~ /\s$/ && $cc =~ /^\s*,/) {

#				# Ignore comments
#				} elsif ($op =~ /^$;+$/) {

				# ; should have either the end of line or a space or \ after it
				} elsif ($op eq ';') {
					if ($ctx !~ /.x[WEBC]/ &&
					    $cc !~ /^\\/ && $cc !~ /^;/) {
						if (ERROR("SPACING",
							  "space required after that '$op' $at\n" . $hereptr)) {
							$good = $fix_elements[$n] . trim($fix_elements[$n + 1]) . " ";
							$line_fixed = 1;
						}
					}

				# // is a comment
				} elsif ($op eq '//') {

				# No spaces for:
				#   ->
				#   :   when part of a bitfield
				} elsif ($op eq '->' || $opv eq ':B') {
					if ($ctx =~ /Wx.|.xW/) {
						if (ERROR("SPACING",
							  "spaces prohibited around that '$op' $at\n" . $hereptr)) {
							$good = rtrim($fix_elements[$n]) . trim($fix_elements[$n + 1]);
							if (defined $fix_elements[$n + 2]) {
								$fix_elements[$n + 2] =~ s/^\s+//;
							}
							$line_fixed = 1;
						}
					}

				# , must have a space on the right.
				} elsif ($op eq ',') {
					if ($ctx !~ /.x[WEC]/ && $cc !~ /^}/) {
						if (ERROR("SPACING",
							  "space required after that '$op' $at\n" . $hereptr)) {
							$good = $fix_elements[$n] . trim($fix_elements[$n + 1]) . " ";
							$line_fixed = 1;
							$last_after = $n;
						}
					}

				# '*' as part of a type definition -- reported already.
				} elsif ($opv eq '*_') {
					#warn "'*' is part of type\n";

				# unary operators should have a space before and
				# none after.  May be left adjacent to another
				# unary operator, or a cast
				} elsif ($op eq '!' || $op eq '~' ||
					 $opv eq '*U' || $opv eq '-U' ||
					 $opv eq '&U' || $opv eq '&&U') {
					if ($ctx !~ /[WEBC]x./ && $ca !~ /(?:\)|!|~|\*|-|\&|\||\+\+|\-\-|\{)$/) {
						if (ERROR("SPACING",
							  "space required before that '$op' $at\n" . $hereptr)) {
							if ($n != $last_after + 2) {
								$good = $fix_elements[$n] . " " . ltrim($fix_elements[$n + 1]);
								$line_fixed = 1;
							}
						}
					}
					if ($op eq '*' && $cc =~/\s*$Modifier\b/) {
						# A unary '*' may be const

					} elsif ($ctx =~ /.xW/) {
						if (ERROR("SPACING",
							  "space prohibited after that '$op' $at\n" . $hereptr)) {
							$good = $fix_elements[$n] . rtrim($fix_elements[$n + 1]);
							if (defined $fix_elements[$n + 2]) {
								$fix_elements[$n + 2] =~ s/^\s+//;
							}
							$line_fixed = 1;
						}
					}

				# unary ++ and unary -- are allowed no space on one side.
				} elsif ($op eq '++' or $op eq '--') {
					if ($ctx !~ /[WEOBC]x[^W]/ && $ctx !~ /[^W]x[WOBEC]/) {
						if (ERROR("SPACING",
							  "space required one side of that '$op' $at\n" . $hereptr)) {
							$good = $fix_elements[$n] . trim($fix_elements[$n + 1]) . " ";
							$line_fixed = 1;
						}
					}
					if ($ctx =~ /Wx[BE]/ ||
					    ($ctx =~ /Wx./ && $cc =~ /^;/)) {
						if (ERROR("SPACING",
							  "space prohibited before that '$op' $at\n" . $hereptr)) {
							$good = rtrim($fix_elements[$n]) . trim($fix_elements[$n + 1]);
							$line_fixed = 1;
						}
					}
					if ($ctx =~ /ExW/) {
						if (ERROR("SPACING",
							  "space prohibited after that '$op' $at\n" . $hereptr)) {
							$good = $fix_elements[$n] . trim($fix_elements[$n + 1]);
							if (defined $fix_elements[$n + 2]) {
								$fix_elements[$n + 2] =~ s/^\s+//;
							}
							$line_fixed = 1;
						}
					}

				# << and >> may either have or not have spaces both sides
				} elsif ($op eq '<<' or $op eq '>>' or
					 $op eq '&' or $op eq '^' or $op eq '|' or
					 $op eq '+' or $op eq '-' or
					 $op eq '*' or $op eq '/' or
					 $op eq '%')
				{
					if ($ctx =~ /Wx[^WCE]|[^WCE]xW/) {
						if (ERROR("SPACING",
							  "need consistent spacing around '$op' $at\n" . $hereptr)) {
							$good = rtrim($fix_elements[$n]) . " " . trim($fix_elements[$n + 1]) . " ";
							if (defined $fix_elements[$n + 2]) {
								$fix_elements[$n + 2] =~ s/^\s+//;
							}
							$line_fixed = 1;
						}
					}

				# A colon needs no spaces before when it is
				# terminating a case value or a label.
				} elsif ($opv eq ':C' || $opv eq ':L') {
					if ($ctx =~ /Wx./) {
						if (ERROR("SPACING",
							  "space prohibited before that '$op' $at\n" . $hereptr)) {
							$good = rtrim($fix_elements[$n]) . trim($fix_elements[$n + 1]);
							$line_fixed = 1;
						}
					}

				# All the others need spaces both sides.
				} elsif ($ctx !~ /[EWC]x[CWE]/) {
					my $ok = 0;

					# Ignore email addresses <foo@bar>
					if (($op eq '<' &&
					     $cc =~ /^\S+\@\S+>/) ||
					    ($op eq '>' &&
					     $ca =~ /<\S+\@\S+$/))
					{
					    	$ok = 1;
					}

					# messages are ERROR, but ?: are CHK
					if ($ok == 0) {
						my $msg_type = \&ERROR;
						$msg_type = \&CHK if (($op eq '?:' || $op eq '?' || $op eq ':') && $ctx =~ /VxV/);

						if (&{$msg_type}("SPACING",
								 "spaces required around that '$op' $at\n" . $hereptr)) {
							$good = rtrim($fix_elements[$n]) . " " . trim($fix_elements[$n + 1]) . " ";
							if (defined $fix_elements[$n + 2]) {
								$fix_elements[$n + 2] =~ s/^\s+//;
							}
							$line_fixed = 1;
						}
					}
				}
				$off += length($elements[$n + 1]);

##				print("n: <$n> GOOD: <$good>\n");

				$fixed_line = $fixed_line . $good;
			}

			if (($#elements % 2) == 0) {
				$fixed_line = $fixed_line . $fix_elements[$#elements];
			}

			if ($fix && $line_fixed && $fixed_line ne $fixed[$linenr - 1]) {
				$fixed[$linenr - 1] = $fixed_line;
			}


		}

# check for whitespace before a non-naked semicolon
		if ($line =~ /^\+.*\S\s+;\s*$/) {
			if (WARN("SPACING",
				 "space prohibited before semicolon\n" . $herecurr) &&
			    $fix) {
				1 while $fixed[$linenr - 1] =~
				    s/^(\+.*\S)\s+;/$1;/;
			}
		}

# check for multiple assignments
		if ($line =~ /^.\s*$Lval\s*=\s*$Lval\s*=(?!=)/) {
			CHK("MULTIPLE_ASSIGNMENTS",
			    "multiple assignments should be avoided\n" . $herecurr);
		}

## # check for multiple declarations, allowing for a function declaration
## # continuation.
## 		if ($line =~ /^.\s*$Type\s+$Ident(?:\s*=[^,{]*)?\s*,\s*$Ident.*/ &&
## 		    $line !~ /^.\s*$Type\s+$Ident(?:\s*=[^,{]*)?\s*,\s*$Type\s*$Ident.*/) {
##
## 			# Remove any bracketed sections to ensure we do not
## 			# falsly report the parameters of functions.
## 			my $ln = $line;
## 			while ($ln =~ s/\([^\(\)]*\)//g) {
## 			}
## 			if ($ln =~ /,/) {
## 				WARN("MULTIPLE_DECLARATION",
##				     "declaring multiple variables together should be avoided\n" . $herecurr);
## 			}
## 		}

#need space before brace following if, while, etc
		if (($line =~ /\(.*\)\{/ && $line !~ /\($Type\){/) ||
		    $line =~ /do\{/) {
			if (ERROR("SPACING",
				  "space required before the open brace '{'\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~ s/^(\+.*(?:do|\))){/$1 {/;
			}
		}

## # check for blank lines before declarations
##		if ($line =~ /^.\t+$Type\s+$Ident(?:\s*=.*)?;/ &&
##		    $prevrawline =~ /^.\s*$/) {
##			WARN("SPACING",
##			     "No blank lines before declarations\n" . $hereprev);
##		}
##

# closing brace should have a space following it when it has anything
# on the line
		if ($line =~ /}(?!(?:,|;|\)))\S/) {
			if (ERROR("SPACING",
				  "space required after that close brace '}'\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/}((?!(?:,|;|\)))\S)/} $1/;
			}
		}

# check spacing on square brackets
		if ($line =~ /\[\s/ && $line !~ /\[\s*$/) {
			if (ERROR("SPACING",
				  "space prohibited after that open square bracket '['\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/\[\s+/\[/;
			}
		}
		if ($line =~ /\s\]/) {
			if (ERROR("SPACING",
				  "space prohibited before that close square bracket ']'\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/\s+\]/\]/;
			}
		}

# check spacing on parentheses
		if ($line =~ /\(\s/ && $line !~ /\(\s*(?:\\)?$/ &&
		    $line !~ /for\s*\(\s+;/) {
			if (ERROR("SPACING",
				  "space prohibited after that open parenthesis '('\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/\(\s+/\(/;
			}
		}
		if ($line =~ /(\s+)\)/ && $line !~ /^.\s*\)/ &&
		    $line !~ /for\s*\(.*;\s+\)/ &&
		    $line !~ /:\s+\)/) {
			if (ERROR("SPACING",
				  "space prohibited before that close parenthesis ')'\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/\s+\)/\)/;
			}
		}

#goto labels aren't indented, allow a single space however
		if ($line=~/^.\s+[A-Za-z\d_]+:(?![0-9]+)/ and
		   !($line=~/^. [A-Za-z\d_]+:/) and !($line=~/^.\s+default:/)) {
			if (WARN("INDENTED_LABEL",
				 "labels should not be indented\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/^(.)\s+/$1/;
			}
		}

# Return is not a function.
		if (defined($stat) && $stat =~ /^.\s*return(\s*)\(/s) {
			my $spacing = $1;
			if ($^V && $^V ge 5.10.0 &&
			    $stat =~ /^.\s*return\s*$balanced_parens\s*;\s*$/) {
				ERROR("RETURN_PARENTHESES",
				      "return is not a function, parentheses are not required\n" . $herecurr);

			} elsif ($spacing !~ /\s+/) {
				ERROR("SPACING",
				      "space required before the open parenthesis '('\n" . $herecurr);
			}
		}

# if statements using unnecessary parentheses - ie: if ((foo == bar))
		if ($^V && $^V ge 5.10.0 &&
		    $line =~ /\bif\s*((?:\(\s*){2,})/) {
			my $openparens = $1;
			my $count = $openparens =~ tr@\(@\(@;
			my $msg = "";
			if ($line =~ /\bif\s*(?:\(\s*){$count,$count}$LvalOrFunc\s*($Compare)\s*$LvalOrFunc(?:\s*\)){$count,$count}/) {
				my $comp = $4;	#Not $1 because of $LvalOrFunc
				$msg = " - maybe == should be = ?" if ($comp eq "==");
				WARN("UNNECESSARY_PARENTHESES",
				     "Unnecessary parentheses$msg\n" . $herecurr);
			}
		}

# Return of what appears to be an errno should normally be -'ve
		if ($line =~ /^.\s*return\s*(E[A-Z]*)\s*;/) {
			my $name = $1;
			if ($name ne 'EOF' && $name ne 'ERROR') {
				WARN("USE_NEGATIVE_ERRNO",
				     "return of an errno should typically be -ve (return -$1)\n" . $herecurr);
			}
		}

# Need a space before open parenthesis after if, while etc
		if ($line =~ /\b(if|while|for|switch)\(/) {
			if (ERROR("SPACING",
				  "space required before the open parenthesis '('\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/\b(if|while|for|switch)\(/$1 \(/;
			}
		}

# Check for illegal assignment in if conditional -- and check for trailing
# statements after the conditional.
		if ($line =~ /do\s*(?!{)/) {
			($stat, $cond, $line_nr_next, $remain_next, $off_next) =
				ctx_statement_block($linenr, $realcnt, 0)
					if (!defined $stat);
			my ($stat_next) = ctx_statement_block($line_nr_next,
						$remain_next, $off_next);
			$stat_next =~ s/\n./\n /g;
			##print "stat<$stat> stat_next<$stat_next>\n";

			if ($stat_next =~ /^\s*while\b/) {
				# If the statement carries leading newlines,
				# then count those as offsets.
				my ($whitespace) =
					($stat_next =~ /^((?:\s*\n[+-])*\s*)/s);
				my $offset =
					statement_rawlines($whitespace) - 1;

				$suppress_whiletrailers{$line_nr_next +
								$offset} = 1;
			}
		}
		if (!defined $suppress_whiletrailers{$linenr} &&
		    defined($stat) && defined($cond) &&
		    $line =~ /\b(?:if|while|for)\s*\(/ && $line !~ /^.\s*#/) {
			my ($s, $c) = ($stat, $cond);

			if ($c =~ /\bif\s*\(.*[^<>!=]=[^=].*/s) {
				ERROR("ASSIGN_IN_IF",
				      "do not use assignment in if condition\n" . $herecurr);
			}

			# Find out what is on the end of the line after the
			# conditional.
			substr($s, 0, length($c), '');
			$s =~ s/\n.*//g;
			$s =~ s/$;//g; 	# Remove any comments
			if (length($c) && $s !~ /^\s*{?\s*\\*\s*$/ &&
			    $c !~ /}\s*while\s*/)
			{
				# Find out how long the conditional actually is.
				my @newlines = ($c =~ /\n/gs);
				my $cond_lines = 1 + $#newlines;
				my $stat_real = '';

				$stat_real = raw_line($linenr, $cond_lines)
							. "\n" if ($cond_lines);
				if (defined($stat_real) && $cond_lines > 1) {
					$stat_real = "[...]\n$stat_real";
				}

				ERROR("TRAILING_STATEMENTS",
				      "trailing statements should be on next line\n" . $herecurr . $stat_real);
			}
		}

# Check for bitwise tests written as boolean
		if ($line =~ /
			(?:
				(?:\[|\(|\&\&|\|\|)
				\s*0[xX][0-9]+\s*
				(?:\&\&|\|\|)
			|
				(?:\&\&|\|\|)
				\s*0[xX][0-9]+\s*
				(?:\&\&|\|\||\)|\])
			)/x)
		{
			WARN("HEXADECIMAL_BOOLEAN_TEST",
			     "boolean test with hexadecimal, perhaps just 1 \& or \|?\n" . $herecurr);
		}

# if and else should not have general statements after it
		if ($line =~ /^.\s*(?:}\s*)?else\b(.*)/) {
			my $s = $1;
			$s =~ s/$;//g; 	# Remove any comments
			if ($s !~ /^\s*(?:\sif|(?:{|)\s*\\?\s*$)/) {
				ERROR("TRAILING_STATEMENTS",
				      "trailing statements should be on next line\n" . $herecurr);
			}
		}
# if should not continue a brace
		if ($line =~ /}\s*if\b/) {
			ERROR("TRAILING_STATEMENTS",
			      "trailing statements should be on next line\n" .
				$herecurr);
		}
# case and default should not have general statements after them
		if ($line =~ /^.\s*(?:case\s*.*|default\s*):/g &&
		    $line !~ /\G(?:
			(?:\s*$;*)(?:\s*{)?(?:\s*$;*)(?:\s*\\)?\s*$|
			\s*return\s+
		    )/xg)
		{
			ERROR("TRAILING_STATEMENTS",
			      "trailing statements should be on next line\n" . $herecurr);
		}

		# Check for }<nl>else {, these must be at the same
		# indent level to be relevant to each other.
		if ($prevline=~/}\s*$/ and $line=~/^.\s*else\s*/ and
						$previndent == $indent) {
			ERROR("ELSE_AFTER_BRACE",
			      "else should follow close brace '}'\n" . $hereprev);
		}

		if ($prevline=~/}\s*$/ and $line=~/^.\s*while\s*/ and
						$previndent == $indent) {
			my ($s, $c) = ctx_statement_block($linenr, $realcnt, 0);

			# Find out what is on the end of the line after the
			# conditional.
			substr($s, 0, length($c), '');
			$s =~ s/\n.*//g;

			if ($s =~ /^\s*;/) {
				ERROR("WHILE_AFTER_BRACE",
				      "while should follow close brace '}'\n" . $hereprev);
			}
		}

#Specific variable tests
		while ($line =~ m{($Constant|$Lval)}g) {
			my $var = $1;

#gcc binary extension
			if ($var =~ /^$Binary$/) {
				if (WARN("GCC_BINARY_CONSTANT",
					 "Avoid gcc v4.3+ binary constant extension: <$var>\n" . $herecurr) &&
				    $fix) {
					my $hexval = sprintf("0x%x", oct($var));
					$fixed[$linenr - 1] =~
					    s/\b$var\b/$hexval/;
				}
			}

#CamelCase
			if ($var !~ /^$Constant$/ &&
			    $var =~ /[A-Z][a-z]|[a-z][A-Z]/ &&
#Ignore Page<foo> variants
			    $var !~ /^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
#Ignore SI style variants like nS, mV and dB (ie: max_uV, regulator_min_uA_show)
			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/) {
				while ($var =~ m{($Ident)}g) {
					my $word = $1;
					next if ($word !~ /[A-Z][a-z]|[a-z][A-Z]/);
					if ($check) {
						seed_camelcase_includes();
						if (!$file && !$camelcase_file_seeded) {
							seed_camelcase_file($realfile);
							$camelcase_file_seeded = 1;
						}
					}
					if (!defined $camelcase{$word}) {
						$camelcase{$word} = 1;
						CHK("CAMELCASE",
						    "Avoid CamelCase: <$word>\n" . $herecurr);
					}
				}
			}
		}

#no spaces allowed after \ in define
		if ($line =~ /\#\s*define.*\\\s+$/) {
			if (WARN("WHITESPACE_AFTER_LINE_CONTINUATION",
				 "Whitespace after \\ makes next lines useless\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~ s/\s+$//;
			}
		}

#warn if <asm/foo.h> is #included and <linux/foo.h> is available (uses RAW line)
		if ($tree && $rawline =~ m{^.\s*\#\s*include\s*\<asm\/(.*)\.h\>}) {
			my $file = "$1.h";
			my $checkfile = "include/linux/$file";
			if (-f "$root/$checkfile" &&
			    $realfile ne $checkfile &&
			    $1 !~ /$allowed_asm_includes/)
			{
				if ($realfile =~ m{^arch/}) {
					CHK("ARCH_INCLUDE_LINUX",
					    "Consider using #include <linux/$file> instead of <asm/$file>\n" . $herecurr);
				} else {
					WARN("INCLUDE_LINUX",
					     "Use #include <linux/$file> instead of <asm/$file>\n" . $herecurr);
				}
			}
		}

# multi-statement macros should be enclosed in a do while loop, grab the
# first statement and ensure its the whole macro if its not enclosed
# in a known good container
		if ($realfile !~ m@/vmlinux.lds.h$@ &&
		    $line =~ /^.\s*\#\s*define\s*$Ident(\()?/) {
			my $ln = $linenr;
			my $cnt = $realcnt;
			my ($off, $dstat, $dcond, $rest);
			my $ctx = '';
			($dstat, $dcond, $ln, $cnt, $off) =
				ctx_statement_block($linenr, $realcnt, 0);
			$ctx = $dstat;
			#print "dstat<$dstat> dcond<$dcond> cnt<$cnt> off<$off>\n";
			#print "LINE<$lines[$ln-1]> len<" . length($lines[$ln-1]) . "\n";

			$dstat =~ s/^.\s*\#\s*define\s+$Ident(?:\([^\)]*\))?\s*//;
			$dstat =~ s/$;//g;
			$dstat =~ s/\\\n.//g;
			$dstat =~ s/^\s*//s;
			$dstat =~ s/\s*$//s;

			# Flatten any parentheses and braces
			while ($dstat =~ s/\([^\(\)]*\)/1/ ||
			       $dstat =~ s/\{[^\{\}]*\}/1/ ||
			       $dstat =~ s/\[[^\[\]]*\]/1/)
			{
			}

			# Flatten any obvious string concatentation.
			while ($dstat =~ s/("X*")\s*$Ident/$1/ ||
			       $dstat =~ s/$Ident\s*("X*")/$1/)
			{
			}

			my $exceptions = qr{
				$Declare|
				module_param_named|
				MODULE_PARM_DESC|
				DECLARE_PER_CPU|
				DEFINE_PER_CPU|
				__typeof__\(|
				union|
				struct|
				\.$Ident\s*=\s*|
				^\"|\"$
			}x;
			#print "REST<$rest> dstat<$dstat> ctx<$ctx>\n";
			if ($dstat ne '' &&
			    $dstat !~ /^(?:$Ident|-?$Constant),$/ &&			# 10, // foo(),
			    $dstat !~ /^(?:$Ident|-?$Constant);$/ &&			# foo();
			    $dstat !~ /^[!~-]?(?:$Lval|$Constant)$/ &&		# 10 // foo() // !foo // ~foo // -foo // foo->bar // foo.bar->baz
			    $dstat !~ /^'X'$/ &&					# character constants
			    $dstat !~ /$exceptions/ &&
			    $dstat !~ /^\.$Ident\s*=/ &&				# .foo =
			    $dstat !~ /^(?:\#\s*$Ident|\#\s*$Constant)\s*$/ &&		# stringification #foo
			    $dstat !~ /^do\s*$Constant\s*while\s*$Constant;?$/ &&	# do {...} while (...); // do {...} while (...)
			    $dstat !~ /^for\s*$Constant$/ &&				# for (...)
			    $dstat !~ /^for\s*$Constant\s+(?:$Ident|-?$Constant)$/ &&	# for (...) bar()
			    $dstat !~ /^do\s*{/ &&					# do {...
			    $dstat !~ /^\(\{/ &&						# ({...
			    $ctx !~ /^.\s*#\s*define\s+TRACE_(?:SYSTEM|INCLUDE_FILE|INCLUDE_PATH)\b/)
			{
				$ctx =~ s/\n*$//;
				my $herectx = $here . "\n";
				my $cnt = statement_rawlines($ctx);

				for (my $n = 0; $n < $cnt; $n++) {
					$herectx .= raw_line($linenr, $n) . "\n";
				}

				if ($dstat =~ /;/) {
					ERROR("MULTISTATEMENT_MACRO_USE_DO_WHILE",
					      "Macros with multiple statements should be enclosed in a do - while loop\n" . "$herectx");
				} else {
					ERROR("COMPLEX_MACRO",
					      "Macros with complex values should be enclosed in parenthesis\n" . "$herectx");
				}
			}

# check for line continuations outside of #defines, preprocessor #, and asm

		} else {
			if ($prevline !~ /^..*\\$/ &&
			    $line !~ /^\+\s*\#.*\\$/ &&		# preprocessor
			    $line !~ /^\+.*\b(__asm__|asm)\b.*\\$/ &&	# asm
			    $line =~ /^\+.*\\$/) {
				WARN("LINE_CONTINUATIONS",
				     "Avoid unnecessary line continuations\n" . $herecurr);
			}
		}

# do {} while (0) macro tests:
# single-statement macros do not need to be enclosed in do while (0) loop,
# macro should not end with a semicolon
		if ($^V && $^V ge 5.10.0 &&
		    $realfile !~ m@/vmlinux.lds.h$@ &&
		    $line =~ /^.\s*\#\s*define\s+$Ident(\()?/) {
			my $ln = $linenr;
			my $cnt = $realcnt;
			my ($off, $dstat, $dcond, $rest);
			my $ctx = '';
			($dstat, $dcond, $ln, $cnt, $off) =
				ctx_statement_block($linenr, $realcnt, 0);
			$ctx = $dstat;

			$dstat =~ s/\\\n.//g;

			if ($dstat =~ /^\+\s*#\s*define\s+$Ident\s*${balanced_parens}\s*do\s*{(.*)\s*}\s*while\s*\(\s*0\s*\)\s*([;\s]*)\s*$/) {
				my $stmts = $2;
				my $semis = $3;

				$ctx =~ s/\n*$//;
				my $cnt = statement_rawlines($ctx);
				my $herectx = $here . "\n";

				for (my $n = 0; $n < $cnt; $n++) {
					$herectx .= raw_line($linenr, $n) . "\n";
				}

				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");
				}
			}
		}

# make sure symbols are always wrapped with VMLINUX_SYMBOL() ...
# all assignments may have only one of the following with an assignment:
#	.
#	ALIGN(...)
#	VMLINUX_SYMBOL(...)
		if ($realfile eq 'vmlinux.lds.h' && $line =~ /(?:(?:^|\s)$Ident\s*=|=\s*$Ident(?:\s|$))/) {
			WARN("MISSING_VMLINUX_SYMBOL",
			     "vmlinux.lds.h needs VMLINUX_SYMBOL() around C-visible symbols\n" . $herecurr);
		}

# check for redundant bracing round if etc
		if ($line =~ /(^.*)\bif\b/ && $1 !~ /else\s*$/) {
			my ($level, $endln, @chunks) =
				ctx_statement_full($linenr, $realcnt, 1);
			#print "chunks<$#chunks> linenr<$linenr> endln<$endln> level<$level>\n";
			#print "APW: <<$chunks[1][0]>><<$chunks[1][1]>>\n";
			if ($#chunks > 0 && $level == 0) {
				my @allowed = ();
				my $allow = 0;
				my $seen = 0;
				my $herectx = $here . "\n";
				my $ln = $linenr - 1;
				for my $chunk (@chunks) {
					my ($cond, $block) = @{$chunk};

					# If the condition carries leading newlines, then count those as offsets.
					my ($whitespace) = ($cond =~ /^((?:\s*\n[+-])*\s*)/s);
					my $offset = statement_rawlines($whitespace) - 1;

					$allowed[$allow] = 0;
					#print "COND<$cond> whitespace<$whitespace> offset<$offset>\n";

					# We have looked at and allowed this specific line.
					$suppress_ifbraces{$ln + $offset} = 1;

					$herectx .= "$rawlines[$ln + $offset]\n[...]\n";
					$ln += statement_rawlines($block) - 1;

					substr($block, 0, length($cond), '');

					$seen++ if ($block =~ /^\s*{/);

					#print "cond<$cond> block<$block> allowed<$allowed[$allow]>\n";
					if (statement_lines($cond) > 1) {
						#print "APW: ALLOWED: cond<$cond>\n";
						$allowed[$allow] = 1;
					}
					if ($block =~/\b(?:if|for|while)\b/) {
						#print "APW: ALLOWED: block<$block>\n";
						$allowed[$allow] = 1;
					}
					if (statement_block_size($block) > 1) {
						#print "APW: ALLOWED: lines block<$block>\n";
						$allowed[$allow] = 1;
					}
					$allow++;
				}
				if ($seen) {
					my $sum_allowed = 0;
					foreach (@allowed) {
						$sum_allowed += $_;
					}
					if ($sum_allowed == 0) {
						WARN("BRACES",
						     "braces {} are not necessary for any arm of this statement\n" . $herectx);
					} elsif ($sum_allowed != $allow &&
						 $seen != $allow) {
						CHK("BRACES",
						    "braces {} should be used on all arms of this statement\n" . $herectx);
					}
				}
			}
		}
		if (!defined $suppress_ifbraces{$linenr - 1} &&
					$line =~ /\b(if|while|for|else)\b/) {
			my $allowed = 0;

			# Check the pre-context.
			if (substr($line, 0, $-[0]) =~ /(\}\s*)$/) {
				#print "APW: ALLOWED: pre<$1>\n";
				$allowed = 1;
			}

			my ($level, $endln, @chunks) =
				ctx_statement_full($linenr, $realcnt, $-[0]);

			# Check the condition.
			my ($cond, $block) = @{$chunks[0]};
			#print "CHECKING<$linenr> cond<$cond> block<$block>\n";
			if (defined $cond) {
				substr($block, 0, length($cond), '');
			}
			if (statement_lines($cond) > 1) {
				#print "APW: ALLOWED: cond<$cond>\n";
				$allowed = 1;
			}
			if ($block =~/\b(?:if|for|while)\b/) {
				#print "APW: ALLOWED: block<$block>\n";
				$allowed = 1;
			}
			if (statement_block_size($block) > 1) {
				#print "APW: ALLOWED: lines block<$block>\n";
				$allowed = 1;
			}
			# Check the post-context.
			if (defined $chunks[1]) {
				my ($cond, $block) = @{$chunks[1]};
				if (defined $cond) {
					substr($block, 0, length($cond), '');
				}
				if ($block =~ /^\s*\{/) {
					#print "APW: ALLOWED: chunk-1 block<$block>\n";
					$allowed = 1;
				}
			}
			if ($level == 0 && $block =~ /^\s*\{/ && !$allowed) {
				my $herectx = $here . "\n";
				my $cnt = statement_rawlines($block);

				for (my $n = 0; $n < $cnt; $n++) {
					$herectx .= raw_line($linenr, $n) . "\n";
				}

				WARN("BRACES",
				     "braces {} are not necessary for single statement blocks\n" . $herectx);
			}
		}

# check for unnecessary blank lines around braces
		if (($line =~ /^.\s*}\s*$/ && $prevrawline =~ /^.\s*$/)) {
			CHK("BRACES",
			    "Blank lines aren't necessary before a close brace '}'\n" . $hereprev);
		}
		if (($rawline =~ /^.\s*$/ && $prevline =~ /^..*{\s*$/)) {
			CHK("BRACES",
			    "Blank lines aren't necessary after an open brace '{'\n" . $hereprev);
		}

# no volatiles please
		my $asm_volatile = qr{\b(__asm__|asm)\s+(__volatile__|volatile)\b};
		if ($line =~ /\bvolatile\b/ && $line !~ /$asm_volatile/) {
			WARN("VOLATILE",
			     "Use of volatile is usually wrong: see Documentation/volatile-considered-harmful.txt\n" . $herecurr);
		}

# warn about #if 0
		if ($line =~ /^.\s*\#\s*if\s+0\b/) {
			CHK("REDUNDANT_CODE",
			    "if this code is redundant consider removing it\n" .
				$herecurr);
		}

# check for needless "if (<foo>) fn(<foo>)" uses
		if ($prevline =~ /\bif\s*\(\s*($Lval)\s*\)/) {
			my $expr = '\s*\(\s*' . quotemeta($1) . '\s*\)\s*;';
			if ($line =~ /\b(kfree|usb_free_urb|debugfs_remove(?:_recursive)?)$expr/) {
				WARN('NEEDLESS_IF',
				     "$1(NULL) is safe this check is probably not required\n" . $hereprev);
			}
		}

# check for bad placement of section $InitAttribute (e.g.: __initdata)
		if ($line =~ /(\b$InitAttribute\b)/) {
			my $attr = $1;
			if ($line =~ /^\+\s*static\s+(?:const\s+)?(?:$attr\s+)?($NonptrTypeWithAttr)\s+(?:$attr\s+)?($Ident(?:\[[^]]*\])?)\s*[=;]/) {
				my $ptr = $1;
				my $var = $2;
				if ((($ptr =~ /\b(union|struct)\s+$attr\b/ &&
				      ERROR("MISPLACED_INIT",
					    "$attr should be placed after $var\n" . $herecurr)) ||
				     ($ptr !~ /\b(union|struct)\s+$attr\b/ &&
				      WARN("MISPLACED_INIT",
					   "$attr should be placed after $var\n" . $herecurr))) &&
				    $fix) {
					$fixed[$linenr - 1] =~ s/(\bstatic\s+(?:const\s+)?)(?:$attr\s+)?($NonptrTypeWithAttr)\s+(?:$attr\s+)?($Ident(?:\[[^]]*\])?)\s*([=;])\s*/"$1" . trim(string_find_replace($2, "\\s*$attr\\s*", " ")) . " " . trim(string_find_replace($3, "\\s*$attr\\s*", "")) . " $attr" . ("$4" eq ";" ? ";" : " = ")/e;
				}
			}
		}

# check for $InitAttributeData (ie: __initdata) with const
		if ($line =~ /\bconst\b/ && $line =~ /($InitAttributeData)/) {
			my $attr = $1;
			$attr =~ /($InitAttributePrefix)(.*)/;
			my $attr_prefix = $1;
			my $attr_type = $2;
			if (ERROR("INIT_ATTRIBUTE",
				  "Use of const init definition must use ${attr_prefix}initconst\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/$InitAttributeData/${attr_prefix}initconst/;
			}
		}

# check for $InitAttributeConst (ie: __initconst) without const
		if ($line !~ /\bconst\b/ && $line =~ /($InitAttributeConst)/) {
			my $attr = $1;
			if (ERROR("INIT_ATTRIBUTE",
				  "Use of $attr requires a separate use of const\n" . $herecurr) &&
			    $fix) {
				my $lead = $fixed[$linenr - 1] =~
				    /(^\+\s*(?:static\s+))/;
				$lead = rtrim($1);
				$lead = "$lead " if ($lead !~ /^\+$/);
				$lead = "${lead}const ";
				$fixed[$linenr - 1] =~ s/(^\+\s*(?:static\s+))/$lead/;
			}
		}

# prefer usleep_range over udelay
		if ($line =~ /\budelay\s*\(\s*(\d+)\s*\)/) {
			# ignore udelay's < 10, however
			if (! ($1 < 10) ) {
				CHK("USLEEP_RANGE",
				    "usleep_range is preferred over udelay; see Documentation/timers/timers-howto.txt\n" . $line);
			}
		}

# warn about unexpectedly long msleep's
		if ($line =~ /\bmsleep\s*\((\d+)\);/) {
			if ($1 < 20) {
				WARN("MSLEEP",
				     "msleep < 20ms can sleep for up to 20ms; see Documentation/timers/timers-howto.txt\n" . $line);
			}
		}

# check for comparisons of jiffies
		if ($line =~ /\bjiffies\s*$Compare|$Compare\s*jiffies\b/) {
			WARN("JIFFIES_COMPARISON",
			     "Comparing jiffies is almost always wrong; prefer time_after, time_before and friends\n" . $herecurr);
		}

# check for comparisons of get_jiffies_64()
		if ($line =~ /\bget_jiffies_64\s*\(\s*\)\s*$Compare|$Compare\s*get_jiffies_64\s*\(\s*\)/) {
			WARN("JIFFIES_COMPARISON",
			     "Comparing get_jiffies_64() is almost always wrong; prefer time_after64, time_before64 and friends\n" . $herecurr);
		}

# warn about #ifdefs in C files
#		if ($line =~ /^.\s*\#\s*if(|n)def/ && ($realfile =~ /\.c$/)) {
#			print "#ifdef in C files should be avoided\n";
#			print "$herecurr";
#			$clean = 0;
#		}

# warn about spacing in #ifdefs
		if ($line =~ /^.\s*\#\s*(ifdef|ifndef|elif)\s\s+/) {
			if (ERROR("SPACING",
				  "exactly one space required after that #$1\n" . $herecurr) &&
			    $fix) {
				$fixed[$linenr - 1] =~
				    s/^(.\s*\#\s*(ifdef|ifndef|elif))\s{2,}/$1 /;
			}

		}

# check for spinlock_t definitions without a comment.
		if ($line =~ /^.\s*(struct\s+mutex|spinlock_t)\s+\S+;/ ||
		    $line =~ /^.\s*(DEFINE_MUTEX)\s*\(/) {
			my $which = $1;
			if (!ctx_has_comment($first_line, $linenr)) {
				CHK("UNCOMMENTED_DEFINITION",
				    "$1 definition without comment\n" . $herecurr);
			}
		}
# check for memory barriers without a comment.
		if ($line =~ /\b(mb|rmb|wmb|read_barrier_depends|smp_mb|smp_rmb|smp_wmb|smp_read_barrier_depends)\(/) {
			if (!ctx_has_comment($first_line, $linenr)) {
				WARN("MEMORY_BARRIER",
				     "memory barrier without comment\n" . $herecurr);
			}
		}
# check of hardware specific defines
		if ($line =~ m@^.\s*\#\s*if.*\b(__i386__|__powerpc64__|__sun__|__s390x__)\b@ && $realfile !~ m@include/asm-@) {
			CHK("ARCH_DEFINES",
			    "architecture specific defines should be avoided\n" .  $herecurr);
		}

# Check that the storage class is at the beginning of a declaration
		if ($line =~ /\b$Storage\b/ && $line !~ /^.\s*$Storage\b/) {
			WARN("STORAGE_CLASS",
			     "storage class should be at the beginning of the declaration\n" . $herecurr)
		}

# check the location of the inline attribute, that it is between
# storage class and type.
		if ($line =~ /\b$Type\s+$Inline\b/ ||
		    $line =~ /\b$Inline\s+$Storage\b/) {
			ERROR("INLINE_LOCATION",
			      "inline keyword should sit between storage class and type\n" . $herecurr);
		}

# Check for __inline__ and __inline, prefer inline
		if ($realfile !~ m@\binclude/uapi/@ &&