mm: debug write deadlocks

[wrt350n-kernel.git] / scripts / checkpatch.pl

#!/usr/bin/perl -w
# (c) 2001, Dave Jones. <davej@codemonkey.org.uk> (the file handling bit)
# (c) 2005, Joel Schopp <jschopp@austin.ibm.com> (the ugly bit)
# (c) 2007, Andy Whitcroft <apw@uk.ibm.com> (new conditions, test suite, etc)
# Licensed under the terms of the GNU GPL License version 2

use strict;

my $P = $0;
$P =~ s@.*/@@g;

my $V = '0.09';

use Getopt::Long qw(:config no_auto_abbrev);

my $quiet = 0;
my $tree = 1;
my $chk_signoff = 1;
my $chk_patch = 1;
my $tst_type = 0;
GetOptions(
        'q|quiet'       => \$quiet,
        'tree!'         => \$tree,
        'signoff!'      => \$chk_signoff,
        'patch!'        => \$chk_patch,
        'test-type!'    => \$tst_type,
) or exit;

my $exit = 0;

if ($#ARGV < 0) {
        print "usage: $P [options] patchfile\n";
        print "version: $V\n";
        print "options: -q           => quiet\n";
        print "         --no-tree    => run without a kernel tree\n";
        exit(1);
}

if ($tree && !top_of_kernel_tree()) {
        print "Must be run from the top-level dir. of a kernel tree\n";
        exit(2);
}

my @dep_includes = ();
my @dep_functions = ();
my $removal = 'Documentation/feature-removal-schedule.txt';
if ($tree && -f $removal) {
        open(REMOVE, "<$removal") || die "$P: $removal: open failed - $!\n";
        while (<REMOVE>) {
                if (/^Check:\s+(.*\S)/) {
                        for my $entry (split(/[, ]+/, $1)) {
                                if ($entry =~ m@include/(.*)@) {
                                        push(@dep_includes, $1);

                                } elsif ($entry !~ m@/@) {
                                        push(@dep_functions, $entry);
                                }
                        }
                }
        }
}

my @rawlines = ();
while (<>) {
        chomp;
        push(@rawlines, $_);
        if (eof(ARGV)) {
                if (!process($ARGV, @rawlines)) {
                        $exit = 1;
                }
                @rawlines = ();
        }
}

exit($exit);

sub top_of_kernel_tree {
        if ((-f "COPYING") && (-f "CREDITS") && (-f "Kbuild") &&
            (-f "MAINTAINERS") && (-f "Makefile") && (-f "README") &&
            (-d "Documentation") && (-d "arch") && (-d "include") &&
            (-d "drivers") && (-d "fs") && (-d "init") && (-d "ipc") &&
            (-d "kernel") && (-d "lib") && (-d "scripts")) {
                return 1;
        }
        return 0;
}

sub expand_tabs {
        my ($str) = @_;

        my $res = '';
        my $n = 0;
        for my $c (split(//, $str)) {
                if ($c eq "\t") {
                        $res .= ' ';
                        $n++;
                        for (; ($n % 8) != 0; $n++) {
                                $res .= ' ';
                        }
                        next;
                }
                $res .= $c;
                $n++;
        }

        return $res;
}

sub line_stats {
        my ($line) = @_;

        # Drop the diff line leader and expand tabs
        $line =~ s/^.//;
        $line = expand_tabs($line);

        # Pick the indent from the front of the line.
        my ($white) = ($line =~ /^(\s*)/);

        return (length($line), length($white));
}

sub sanitise_line {
        my ($line) = @_;

        my $res = '';
        my $l = '';

        my $quote = '';

        foreach my $c (split(//, $line)) {
                if ($l ne "\\" && ($c eq "'" || $c eq '"')) {
                        if ($quote eq '') {
                                $quote = $c;
                                $res .= $c;
                                $l = $c;
                                next;
                        } elsif ($quote eq $c) {
                                $quote = '';
                        }
                }
                if ($quote && $c ne "\t") {
                        $res .= "X";
                } else {
                        $res .= $c;
                }

                $l = $c;
        }

        return $res;
}

sub ctx_block_get {
        my ($linenr, $remain, $outer, $open, $close, $off) = @_;
        my $line;
        my $start = $linenr - 1;
        my $blk = '';
        my @o;
        my @c;
        my @res = ();

        my $level = 0;
        for ($line = $start; $remain > 0; $line++) {
                next if ($rawlines[$line] =~ /^-/);
                $remain--;

                $blk .= $rawlines[$line];
                foreach my $c (split(//, $rawlines[$line])) {
                        ##print "C<$c>L<$level><$open$close>O<$off>\n";
                        if ($off > 0) {
                                $off--;
                                next;
                        }

                        if ($c eq $close && $level > 0) {
                                $level--;
                                last if ($level == 0);
                        } elsif ($c eq $open) {
                                $level++;
                        }
                }

                if (!$outer || $level <= 1) {
                        push(@res, $rawlines[$line]);
                }

                last if ($level == 0);
        }

        return ($level, @res);
}
sub ctx_block_outer {
        my ($linenr, $remain) = @_;

        my ($level, @r) = ctx_block_get($linenr, $remain, 1, '{', '}', 0);
        return @r;
}
sub ctx_block {
        my ($linenr, $remain) = @_;

        my ($level, @r) = ctx_block_get($linenr, $remain, 0, '{', '}', 0);
        return @r;
}
sub ctx_statement {
        my ($linenr, $remain, $off) = @_;

        my ($level, @r) = ctx_block_get($linenr, $remain, 0, '(', ')', $off);
        return @r;
}
sub ctx_block_level {
        my ($linenr, $remain) = @_;

        return ctx_block_get($linenr, $remain, 0, '{', '}', 0);
}

sub ctx_locate_comment {
        my ($first_line, $end_line) = @_;

        # Catch a comment on the end of the line itself.
        my ($current_comment) = ($rawlines[$end_line - 1] =~ m@.*(/\*.*\*/)\s*$@);
        return $current_comment if (defined $current_comment);

        # Look through the context and try and figure out if there is a
        # comment.
        my $in_comment = 0;
        $current_comment = '';
        for (my $linenr = $first_line; $linenr < $end_line; $linenr++) {
                my $line = $rawlines[$linenr - 1];
                #warn "           $line\n";
                if ($linenr == $first_line and $line =~ m@^.\s*\*@) {
                        $in_comment = 1;
                }
                if ($line =~ m@/\*@) {
                        $in_comment = 1;
                }
                if (!$in_comment && $current_comment ne '') {
                        $current_comment = '';
                }
                $current_comment .= $line . "\n" if ($in_comment);
                if ($line =~ m@\*/@) {
                        $in_comment = 0;
                }
        }

        chomp($current_comment);
        return($current_comment);
}
sub ctx_has_comment {
        my ($first_line, $end_line) = @_;
        my $cmt = ctx_locate_comment($first_line, $end_line);

        ##print "LINE: $rawlines[$end_line - 1 ]\n";
        ##print "CMMT: $cmt\n";

        return ($cmt ne '');
}

sub cat_vet {
        my ($vet) = @_;

        $vet =~ s/\t/^I/;
        $vet =~ s/$/\$/;

        return $vet;
}

my @report = ();
sub report {
        push(@report, $_[0]);
}
sub report_dump {
        @report;
}
sub ERROR {
        report("ERROR: $_[0]\n");
        our $clean = 0;
}
sub WARN {
        report("WARNING: $_[0]\n");
        our $clean = 0;
}
sub CHK {
        report("CHECK: $_[0]\n");
        our $clean = 0;
}

sub process {
        my $filename = shift;
        my @lines = @_;

        my $linenr=0;
        my $prevline="";
        my $stashline="";

        my $length;
        my $indent;
        my $previndent=0;
        my $stashindent=0;

        our $clean = 1;
        my $signoff = 0;
        my $is_patch = 0;

        # Trace the real file/line as we go.
        my $realfile = '';
        my $realline = 0;
        my $realcnt = 0;
        my $here = '';
        my $in_comment = 0;
        my $first_line = 0;

        my $Ident       = qr{[A-Za-z\d_]+};
        my $Storage     = qr{extern|static};
        my $Sparse      = qr{__user|__kernel|__force|__iomem|__must_check|__init_refok};
        my $NonptrType  = qr{
                                \b
                                (?:const\s+)?
                                (?:unsigned\s+)?
                                (?:
                                        void|
                                        char|
                                        short|
                                        int|
                                        long|
                                        unsigned|
                                        float|
                                        double|
                                        bool|
                                        long\s+int|
                                        long\s+long|
                                        long\s+long\s+int|
                                        u8|u16|u32|u64|
                                        s8|s16|s32|s64|
                                        struct\s+$Ident|
                                        union\s+$Ident|
                                        enum\s+$Ident|
                                        ${Ident}_t
                                )
                                (?:\s+$Sparse)*
                                \b
                          }x;
        my $Type        = qr{
                                \b$NonptrType\b
                                (?:\s*\*+\s*const|\s*\*+|(?:\s*\[\s*\])+)?
                                (?:\s+$Sparse)*
                          }x;
        my $Declare     = qr{(?:$Storage\s+)?$Type};
        my $Attribute   = qr{const|__read_mostly|__init|__initdata|__meminit};

        my $Member      = qr{->$Ident|\.$Ident|\[[^]]*\]};
        my $Lval        = qr{$Ident(?:$Member)*};

        # Pre-scan the patch looking for any __setup documentation.
        my @setup_docs = ();
        my $setup_docs = 0;
        foreach my $line (@lines) {
                if ($line=~/^\+\+\+\s+(\S+)/) {
                        $setup_docs = 0;
                        if ($1 =~ m@Documentation/kernel-parameters.txt$@) {
                                $setup_docs = 1;
                        }
                        next;
                }

                if ($setup_docs && $line =~ /^\+/) {
                        push(@setup_docs, $line);
                }
        }

        foreach my $line (@lines) {
                $linenr++;

                my $rawline = $line;

#extract the filename as it passes
                if ($line=~/^\+\+\+\s+(\S+)/) {
                        $realfile=$1;
                        $realfile =~ s@^[^/]*/@@;
                        $in_comment = 0;
                        next;
                }
#extract the line range in the file after the patch is applied
                if ($line=~/^\@\@ -\d+,\d+ \+(\d+)(,(\d+))? \@\@/) {
                        $is_patch = 1;
                        $first_line = $linenr + 1;
                        $in_comment = 0;
                        $realline=$1-1;
                        if (defined $2) {
                                $realcnt=$3+1;
                        } else {
                                $realcnt=1+1;
                        }
                        next;
                }

# track the line number as we move through the hunk, note that
# new versions of GNU diff omit the leading space on completely
# blank context lines so we need to count that too.
                if ($line =~ /^( |\+|$)/) {
                        $realline++;
                        $realcnt-- if ($realcnt != 0);

                        # track any sort of multi-line comment.  Obviously if
                        # the added text or context do not include the whole
                        # comment we will not see it. Such is life.
                        #
                        # Guestimate if this is a continuing comment.  If this
                        # is the start of a diff block and this line starts
                        # ' *' then it is very likely a comment.
                        if ($linenr == $first_line and $line =~ m@^.\s*\*@) {
                                $in_comment = 1;
                        }
                        if ($line =~ m@/\*@) {
                                $in_comment = 1;
                        }
                        if ($line =~ m@\*/@) {
                                $in_comment = 0;
                        }

                        # Measure the line length and indent.
                        ($length, $indent) = line_stats($line);

                        # Track the previous line.
                        ($prevline, $stashline) = ($stashline, $line);
                        ($previndent, $stashindent) = ($stashindent, $indent);
                } elsif ($realcnt == 1) {
                        $realcnt--;
                }

#make up the handle for any error we report on this line
                $here = "#$linenr: ";
                $here .= "FILE: $realfile:$realline:" if ($realcnt != 0);

                my $hereline = "$here\n$line\n";
                my $herecurr = "$here\n$line\n";
                my $hereprev = "$here\n$prevline\n$line\n";

#check the patch for a signoff:
                if ($line =~ /^\s*signed-off-by:/i) {
                        # This is a signoff, if ugly, so do not double report.
                        $signoff++;
                        if (!($line =~ /^\s*Signed-off-by:/)) {
                                WARN("Signed-off-by: is the preferred form\n" .
                                        $herecurr);
                        }
                        if ($line =~ /^\s*signed-off-by:\S/i) {
                                WARN("need space after Signed-off-by:\n" .
                                        $herecurr);
                        }
                }

# Check for wrappage within a valid hunk of the file
                if ($realcnt != 0 && $line !~ m{^(?:\+|-| |$)}) {
                        ERROR("patch seems to be corrupt (line wrapped?)\n" .
                                $herecurr);
                }

# UTF-8 regex found at http://www.w3.org/International/questions/qa-forms-utf-8.en.php
                if (($realfile =~ /^$/ || $line =~ /^\+/) &&
                     !($line =~ m/^(
                                [\x09\x0A\x0D\x20-\x7E]              # ASCII
                                | [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
                                |  \xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
                                | [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
                                |  \xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
                                |  \xF0[\x90-\xBF][\x80-\xBF]{2}     # planes 1-3
                                | [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
                                |  \xF4[\x80-\x8F][\x80-\xBF]{2}     # plane 16
                                )*$/x )) {
                        ERROR("Invalid UTF-8\n" . $herecurr);
                }

#ignore lines being removed
                if ($line=~/^-/) {next;}

# check we are in a valid source file if not then ignore this hunk
                next if ($realfile !~ /\.(h|c|s|S|pl|sh)$/);

#trailing whitespace
                if ($line =~ /^\+.*\S\s+$/ || $line =~ /^\+\s+$/) {
                        my $herevet = "$here\n" . cat_vet($line) . "\n";
                        ERROR("trailing whitespace\n" . $herevet);
                }
#80 column limit
                if ($line =~ /^\+/ && !($prevline=~/\/\*\*/) && $length > 80) {
                        WARN("line over 80 characters\n" . $herecurr);
                }

# check we are in a valid source file *.[hc] if not then ignore this hunk
                next if ($realfile !~ /\.[hc]$/);

# at the beginning of a line any tabs must come first and anything
# more than 8 must use tabs.
                if ($line=~/^\+\s* \t\s*\S/ or $line=~/^\+\s*        \s*/) {
                        my $herevet = "$here\n" . cat_vet($line) . "\n";
                        ERROR("use tabs not spaces\n" . $herevet);
                }

# Remove comments from the line before processing.
                my $comment_edge = ($line =~ s@/\*.*\*/@@g) +
                                   ($line =~ s@/\*.*@@) +
                                   ($line =~ s@^(.).*\*/@$1@);

# The rest of our checks refer specifically to C style
# only apply those _outside_ comments.  Only skip
# lines in the middle of comments.
                next if (!$comment_edge && $in_comment);

# Standardise the strings and chars within the input to simplify matching.
                $line = sanitise_line($line);

#
# Checks which may be anchored in the context.
#

# Check for switch () and associated case and default
# statements should be at the same indent.
                if ($line=~/\bswitch\s*\(.*\)/) {
                        my $err = '';
                        my $sep = '';
                        my @ctx = ctx_block_outer($linenr, $realcnt);
                        shift(@ctx);
                        for my $ctx (@ctx) {
                                my ($clen, $cindent) = line_stats($ctx);
                                if ($ctx =~ /^\+\s*(case\s+|default:)/ &&
                                                        $indent != $cindent) {
                                        $err .= "$sep$ctx\n";
                                        $sep = '';
                                } else {
                                        $sep = "[...]\n";
                                }
                        }
                        if ($err ne '') {
                                ERROR("switch and case should be at the same indent\n$hereline\n$err\n");
                        }
                }

# if/while/etc brace do not go on next line, unless defining a do while loop,
# or if that brace on the next line is for something else
                if ($line =~ /\b(?:(if|while|for|switch)\s*\(|do\b|else\b)/ && $line !~ /^.#/) {
                        my @ctx = ctx_statement($linenr, $realcnt, 0);
                        my $ctx_ln = $linenr + $#ctx + 1;
                        my $ctx_cnt = $realcnt - $#ctx - 1;
                        my $ctx = join("\n", @ctx);

                        while ($ctx_cnt > 0 && $lines[$ctx_ln - 1] =~ /^-/) {
                                $ctx_ln++;
                                $ctx_cnt--;
                        }
                        ##warn "line<$line>\nctx<$ctx>\nnext<$lines[$ctx_ln - 1]>";

                        if ($ctx !~ /{\s*/ && $ctx_cnt > 0 && $lines[$ctx_ln - 1] =~ /^\+\s*{/) {
                                ERROR("That open brace { should be on the previous line\n" .
                                        "$here\n$ctx\n$lines[$ctx_ln - 1]");
                        }
                }

#ignore lines not being added
                if ($line=~/^[^\+]/) {next;}

# TEST: allow direct testing of the type matcher.
                if ($tst_type && $line =~ /^.$Declare$/) {
                        ERROR("TEST: is type $Declare\n" . $herecurr);
                        next;
                }

# check for initialisation to aggregates open brace on the next line
                if ($prevline =~ /$Declare\s*$Ident\s*=\s*$/ &&
                    $line =~ /^.\s*{/) {
                        ERROR("That open brace { should be on the previous line\n" . $hereprev);
                }

#
# Checks which are anchored on the added line.
#

# check for malformed paths in #include statements (uses RAW line)
                if ($rawline =~ m{^.#\s*include\s+[<"](.*)[">]}) {
                        my $path = $1;
                        if ($path =~ m{//}) {
                                ERROR("malformed #include filename\n" .
                                        $herecurr);
                        }
                        # Sanitise this special form of string.
                        $path = 'X' x length($path);
                        $line =~ s{\<.*\>}{<$path>};
                }

# no C99 // comments
                if ($line =~ m{//}) {
                        ERROR("do not use C99 // comments\n" . $herecurr);
                }
                # Remove C99 comments.
                $line =~ s@//.*@@;

#EXPORT_SYMBOL should immediately follow its function closing }.
                if (($line =~ /EXPORT_SYMBOL.*\((.*)\)/) ||
                    ($line =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
                        my $name = $1;
                        if (($prevline !~ /^}/) &&
                           ($prevline !~ /^\+}/) &&
                           ($prevline !~ /^ }/) &&
                           ($prevline !~ /\b\Q$name\E(?:\s+$Attribute)?\s*(?:;|=)/)) {
                                WARN("EXPORT_SYMBOL(foo); should immediately follow its function/variable\n" . $herecurr);
                        }
                }

# check for external initialisers.
                if ($line =~ /^.$Type\s*$Ident\s*=\s*(0|NULL);/) {
                        ERROR("do not initialise externals to 0 or NULL\n" .
                                $herecurr);
                }
# check for static initialisers.
                if ($line =~ /\s*static\s.*=\s*(0|NULL);/) {
                        ERROR("do not initialise statics to 0 or NULL\n" .
                                $herecurr);
                }

# check for new typedefs, only function parameters and sparse annotations
# make sense.
                if ($line =~ /\btypedef\s/ &&
                    $line !~ /\btypedef\s+$Type\s+\(\s*\*$Ident\s*\)\s*\(/ &&
                    $line !~ /\b__bitwise(?:__|)\b/) {
                        WARN("do not add new typedefs\n" . $herecurr);
                }

# * goes on variable not on type
                if ($line =~ m{\($NonptrType(\*+)(?:\s+const)?\)}) {
                        ERROR("\"(foo$1)\" should be \"(foo $1)\"\n" .
                                $herecurr);

                } elsif ($line =~ m{\($NonptrType\s+(\*+)(?!\s+const)\s+\)}) {
                        ERROR("\"(foo $1 )\" should be \"(foo $1)\"\n" .
                                $herecurr);

                } elsif ($line =~ m{$NonptrType(\*+)(?:\s+$Attribute)?\s+[A-Za-z\d_]+}) {
                        ERROR("\"foo$1 bar\" should be \"foo $1bar\"\n" .
                                $herecurr);

                } elsif ($line =~ m{$NonptrType\s+(\*+)(?!\s+$Attribute)\s+[A-Za-z\d_]+}) {
                        ERROR("\"foo $1 bar\" should be \"foo $1bar\"\n" .
                                $herecurr);
                }

# # no BUG() or BUG_ON()
#               if ($line =~ /\b(BUG|BUG_ON)\b/) {
#                       print "Try to use WARN_ON & Recovery code rather than BUG() or BUG_ON()\n";
#                       print "$herecurr";
#                       $clean = 0;
#               }

# printk should use KERN_* levels.  Note that follow on printk's on the
# same line do not need a level, so we use the current block context
# to try and find and validate the current printk.  In summary the current
# printk includes all preceeding printk's which have no newline on the end.
# we assume the first bad printk is the one to report.
                if ($line =~ /\bprintk\((?!KERN_)\s*"/) {
                        my $ok = 0;
                        for (my $ln = $linenr - 1; $ln >= $first_line; $ln--) {
                                #print "CHECK<$lines[$ln - 1]\n";
                                # we have a preceeding printk if it ends
                                # with "\n" ignore it, else it is to blame
                                if ($lines[$ln - 1] =~ m{\bprintk\(}) {
                                        if ($rawlines[$ln - 1] !~ m{\\n"}) {
                                                $ok = 1;
                                        }
                                        last;
                                }
                        }
                        if ($ok == 0) {
                                WARN("printk() should include KERN_ facility level\n" . $herecurr);
                        }
                }

# function brace can't be on same line, except for #defines of do while,
# or if closed on same line
                if (($line=~/$Type\s*[A-Za-z\d_]+\(.*\).* {/) and
                    !($line=~/\#define.*do\s{/) and !($line=~/}/)) {
                        ERROR("open brace '{' following function declarations go on the next line\n" . $herecurr);
                }

# check for spaces between functions and their parentheses.
                if ($line =~ /($Ident)\s+\(/ &&
                    $1 !~ /^(?:if|for|while|switch|return|volatile|__volatile__|__attribute__|format|__extension__|Copyright)$/ &&
                    $line !~ /$Type\s+\(/ && $line !~ /^.\#\s*define\b/) {
                        WARN("no space between function name and open parenthesis '('\n" . $herecurr);
                }
# Check operator spacing.
                # Note we expand the line with the leading + as the real
                # line will be displayed with the leading + and the tabs
                # will therefore also expand that way.
                my $opline = $line;
                $opline = expand_tabs($opline);
                $opline =~ s/^./ /;
                if (!($line=~/\#\s*include/)) {
                        my @elements = split(/(<<=|>>=|<=|>=|==|!=|\+=|-=|\*=|\/=|%=|\^=|\|=|&=|=>|->|<<|>>|<|>|=|!|~|&&|\|\||,|\^|\+\+|--|;|&|\||\+|-|\*|\/\/|\/)/, $opline);
                        my $off = 0;
                        for (my $n = 0; $n < $#elements; $n += 2) {
                                $off += length($elements[$n]);

                                my $a = '';
                                $a = 'V' if ($elements[$n] ne '');
                                $a = 'W' if ($elements[$n] =~ /\s$/);
                                $a = 'B' if ($elements[$n] =~ /(\[|\()$/);
                                $a = 'O' if ($elements[$n] eq '');
                                $a = 'E' if ($elements[$n] eq '' && $n == 0);

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

                                # Pick up the preceeding 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 $ctx = "${a}x${c}";

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

                                my $ptr = (" " x $off) . "^";
                                my $hereptr = "$hereline$ptr\n";

                                ##print "<$s1:$op:$s2> <$elements[$n]:$elements[$n + 1]:$elements[$n + 2]>\n";

                                # ; should have either the end of line or a space or \ after it
                                if ($op eq ';') {
                                        if ($ctx !~ /.x[WEB]/ && $cc !~ /^\\/ &&
                                            $cc !~ /^;/) {
                                                ERROR("need space after that '$op' $at\n" . $hereptr);
                                        }

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

                                # -> should have no spaces
                                } elsif ($op eq '->') {
                                        if ($ctx =~ /Wx.|.xW/) {
                                                ERROR("no spaces around that '$op' $at\n" . $hereptr);
                                        }

                                # , must have a space on the right.
                                } elsif ($op eq ',') {
                                        if ($ctx !~ /.xW|.xE/ && $cc !~ /^}/) {
                                                ERROR("need space after that '$op' $at\n" . $hereptr);
                                        }

                                # unary ! and unary ~ are allowed no space on the right
                                } elsif ($op eq '!' or $op eq '~') {
                                        if ($ctx !~ /[WOEB]x./) {
                                                ERROR("need space before that '$op' $at\n" . $hereptr);
                                        }
                                        if ($ctx =~ /.xW/) {
                                                ERROR("no space after that '$op' $at\n" . $hereptr);
                                        }

                                # unary ++ and unary -- are allowed no space on one side.
                                } elsif ($op eq '++' or $op eq '--') {
                                        if ($ctx !~ /[WOB]x[^W]/ && $ctx !~ /[^W]x[WOBE]/) {
                                                ERROR("need space one side of that '$op' $at\n" . $hereptr);
                                        }
                                        if ($ctx =~ /Wx./ && $cc =~ /^;/) {
                                                ERROR("no space before that '$op' $at\n" . $hereptr);
                                        }

                                # & is both unary and binary
                                # unary:
                                #       a &b
                                # binary (consistent spacing):
                                #       a&b             OK
                                #       a & b           OK
                                #
                                # boiling down to: if there is a space on the right then there
                                # should be one on the left.
                                #
                                # - is the same
                                #
                                } elsif ($op eq '&' or $op eq '-') {
                                        if ($ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]/) {
                                                ERROR("need space before that '$op' $at\n" . $hereptr);
                                        }

                                # * is the same as & only adding:
                                # type:
                                #       (foo *)
                                #       (foo **)
                                #
                                } elsif ($op eq '*') {
                                        if ($ca !~ /$Type$/ && $cb !~ /(\*$;|$;\*)/ &&
                                            $ctx !~ /VxV|[EW]x[WE]|[EWB]x[VO]|OxV|WxB|BxB/) {
                                                ERROR("need space before that '$op' $at\n" . $hereptr);
                                        }

                                # << 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 $op eq '|')
                                {
                                        if ($ctx !~ /VxV|WxW|VxE|WxE/) {
                                                ERROR("need consistent spacing around '$op' $at\n" .
                                                        $hereptr);
                                        }

                                # All the others need spaces both sides.
                                } elsif ($ctx !~ /[EW]x[WE]/) {
                                        # Ignore email addresses <foo@bar>
                                        if (!($op eq '<' && $cb =~ /$;\S+\@\S+>/) &&
                                            !($op eq '>' && $cb =~ /<\S+\@\S+$;/)) {
                                                ERROR("need spaces around that '$op' $at\n" . $hereptr);
                                        }
                                }
                                $off += length($elements[$n + 1]);
                        }
                }

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

#need space before brace following if, while, etc
                if (($line =~ /\(.*\){/ && $line !~ /\($Type\){/) ||
                    $line =~ /do{/) {
                        ERROR("need a space before the open brace '{'\n" . $herecurr);
                }

# closing brace should have a space following it when it has anything
# on the line
                if ($line =~ /}(?!(?:,|;|\)))\S/) {
                        ERROR("need a space after that close brace '}'\n" . $herecurr);
                }

# check spacing on square brackets
                if ($line =~ /\[\s/ && $line !~ /\[\s*$/) {
                        ERROR("no space after that open square bracket '['\n" . $herecurr);
                }
                if ($line =~ /\s\]/) {
                        ERROR("no space before that close square bracket ']'\n" . $herecurr);
                }

# check spacing on paretheses
                if ($line =~ /\(\s/ && $line !~ /\(\s*$/) {
                        ERROR("no space after that open parenthesis '('\n" . $herecurr);
                }
                if ($line =~ /\s\)/) {
                        ERROR("no space before that close parenthesis ')'\n" . $herecurr);
                }

#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:/)) {
                        WARN("labels should not be indented\n" . $herecurr);
                }

# Need a space before open parenthesis after if, while etc
                if ($line=~/\b(if|while|for|switch)\(/) {
                        ERROR("need a space before the open parenthesis '('\n" . $herecurr);
                }

# Check for illegal assignment in if conditional.
                if ($line=~/\bif\s*\(.*[^<>!=]=[^=].*\)/) {
                        #next if ($line=~/\".*\Q$op\E.*\"/ or $line=~/\'\Q$op\E\'/);
                        ERROR("do not use assignment in if condition\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 should follow close brace '}'\n" . $hereprev);
                }

#studly caps, commented out until figure out how to distinguish between use of existing and adding new
#               if (($line=~/[\w_][a-z\d]+[A-Z]/) and !($line=~/print/)) {
#                   print "No studly caps, use _\n";
#                   print "$herecurr";
#                   $clean = 0;
#               }

#no spaces allowed after \ in define
                if ($line=~/\#define.*\\\s$/) {
                        WARN("Whitepspace after \\ makes next lines useless\n" . $herecurr);
                }

#warn if <asm/foo.h> is #included and <linux/foo.h> is available (uses RAW line)
                if ($tree && $rawline =~ m{^.\#\s*include\s*\<asm\/(.*)\.h\>}) {
                        my $checkfile = "include/linux/$1.h";
                        if (-f $checkfile) {
                                CHK("Use #include <linux/$1.h> instead of <asm/$1.h>\n" .
                                        $herecurr);
                        }
                }

# if and else should not have general statements after it
                if ($line =~ /^.\s*(?:}\s*)?else\b(.*)/ &&
                    $1 !~ /^\s*(?:\sif|{|\\|$)/) {
                        ERROR("trailing statements should be on next line\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 goot container
                if (($prevline=~/\#define.*\\/) and
                   !($prevline=~/do\s+{/) and !($prevline=~/\(\{/) and
                   !($line=~/do.*{/) and !($line=~/\(\{/) and
                   !($line=~/^.\s*$Declare\s/)) {
                        # Grab the first statement, if that is the entire macro
                        # its ok.  This may start either on the #define line
                        # or the one below.
                        my $ln = $linenr;
                        my $cnt = $realcnt;
                        my $off = 0;

                        # If the macro starts on the define line start
                        # grabbing the statement after the identifier
                        $prevline =~ m{^(.#\s*define\s*$Ident(?:\([^\)]*\))?\s*)(.*)\\\s*$};
                        ##print "1<$1> 2<$2>\n";
                        if (defined $2 && $2 ne '') {
                                $off = length($1);
                                $ln--;
                                $cnt++;
                        }
                        my @ctx = ctx_statement($ln, $cnt, $off);
                        my $ctx_ln = $ln + $#ctx + 1;
                        my $ctx = join("\n", @ctx);

                        # Pull in any empty extension lines.
                        while ($ctx =~ /\\$/ &&
                               $lines[$ctx_ln - 1] =~ /^.\s*(?:\\)?$/) {
                                $ctx .= $lines[$ctx_ln - 1];
                                $ctx_ln++;
                        }

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

# check for redundant bracing round if etc
                if ($line =~ /\b(if|while|for|else)\b/) {
                        # Locate the end of the opening statement.
                        my @control = ctx_statement($linenr, $realcnt, 0);
                        my $nr = $linenr + (scalar(@control) - 1);
                        my $cnt = $realcnt - (scalar(@control) - 1);

                        my $off = $realcnt - $cnt;
                        #print "$off: line<$line>end<" . $lines[$nr - 1] . ">\n";

                        # If this is is a braced statement group check it
                        if ($lines[$nr - 1] =~ /{\s*$/) {
                                my ($lvl, @block) = ctx_block_level($nr, $cnt);

                                my $stmt = join(' ', @block);
                                $stmt =~ s/(^[^{]*){//;
                                my $before = $1;
                                $stmt =~ s/}([^}]*$)//;
                                my $after = $1;

                                #print "block<" . join(' ', @block) . "><" . scalar(@block) . ">\n";
                                #print "stmt<$stmt>\n\n";

                                # Count the ;'s if there is fewer than two
                                # then there can only be one statement,
                                # if there is a brace inside we cannot
                                # trivially detect if its one statement.
                                # Also nested if's often require braces to
                                # disambiguate the else binding so shhh there.
                                my @semi = ($stmt =~ /;/g);
                                push(@semi, "/**/") if ($stmt =~ m@/\*@);
                                ##print "semi<" . scalar(@semi) . ">\n";
                                if ($lvl == 0 && scalar(@semi) < 2 &&
                                    $stmt !~ /{/ && $stmt !~ /\bif\b/ &&
                                    $before !~ /}/ && $after !~ /{/) {
                                        my $herectx = "$here\n" . join("\n", @control, @block[1 .. $#block]) . "\n";
                                        shift(@block);
                                        WARN("braces {} are not necessary for single statement blocks\n" . $herectx);
                                }
                        }
                }

# don't include deprecated include files (uses RAW line)
                for my $inc (@dep_includes) {
                        if ($rawline =~ m@\#\s*include\s*\<$inc>@) {
                                ERROR("Don't use <$inc>: see Documentation/feature-removal-schedule.txt\n" . $herecurr);
                        }
                }

# don't use deprecated functions
                for my $func (@dep_functions) {
                        if ($line =~ /\b$func\b/) {
                                ERROR("Don't use $func(): see Documentation/feature-removal-schedule.txt\n" . $herecurr);
                        }
                }

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

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

# check for needless kfree() checks
                if ($prevline =~ /\bif\s*\(([^\)]*)\)/) {
                        my $expr = $1;
                        if ($line =~ /\bkfree\(\Q$expr\E\);/) {
                                WARN("kfree(NULL) is safe this check is probabally not required\n" . $hereprev);
                        }
                }

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

# warn about spacing in #ifdefs
                if ($line =~ /^.#\s*(ifdef|ifndef|elif)\s\s+/) {
                        ERROR("exactly one space required after that #$1\n" . $herecurr);
                }

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

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

# check for new externs in .c files.
                if ($line =~ /^.\s*extern\s/ && ($realfile =~ /\.c$/)) {
                        WARN("externs should be avoided in .c files\n" .  $herecurr);
                }

# checks for new __setup's
                if ($rawline =~ /\b__setup\("([^"]*)"/) {
                        my $name = $1;

                        if (!grep(/$name/, @setup_docs)) {
                                CHK("__setup appears un-documented -- check Documentation/kernel-parameters.txt\n" . $herecurr);
                        }
                }
        }

        if ($chk_patch && !$is_patch) {
                ERROR("Does not appear to be a unified-diff format patch\n");
        }
        if ($is_patch && $chk_signoff && $signoff == 0) {
                ERROR("Missing Signed-off-by: line(s)\n");
        }

        if ($clean == 0 && ($chk_patch || $is_patch)) {
                print report_dump();
        }
        if ($clean == 1 && $quiet == 0) {
                print "Your patch has no obvious style problems and is ready for submission.\n"
        }
        if ($clean == 0 && $quiet == 0) {
                print "Your patch has style problems, please review.  If any of these errors\n";
                print "are false positives report them to the maintainer, see\n";
                print "CHECKPATCH in MAINTAINERS.\n";
        }
        return $clean;
}