From 7d2367af0b09f8028dc5c1b1919bb82d141c2afb Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Mon, 25 Jul 2011 17:13:22 -0700 Subject: [PATCH] checkpatch: suggest using min_t or max_t A common issue with min() or max() is using a cast on one or both of the arguments when using min_t/max_t could be better. Add cast detection to uses of min/max and suggest an appropriate use of min_t or max_t instead. Caveat: This only works for min() or max() on a single line. It does not find min() or max() split across multiple lines. This does find: min((u32)foo, bar); But it does not find: max((unsigned long)foo, bar); Suggested-by: Andrew Morton Signed-off-by: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/checkpatch.pl | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index b0aa2c680593..5ba62d8b5e52 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -268,6 +268,20 @@ sub build_types { } build_types(); +our $match_balanced_parentheses = qr/(\((?:[^\(\)]+|(-1))*\))/; + +our $Typecast = qr{\s*(\(\s*$NonptrType\s*\)){0,1}\s*}; +our $LvalOrFunc = qr{($Lval)\s*($match_balanced_parentheses{0,1})\s*}; + +sub deparenthesize { + my ($string) = @_; + return "" if (!defined($string)); + $string =~ s@^\s*\(\s*@@g; + $string =~ s@\s*\)\s*$@@g; + $string =~ s@\s+@ @g; + return $string; +} + $chk_signoff = 0 if ($file); my @dep_includes = (); @@ -2290,6 +2304,27 @@ sub process { } } +# typecasts on min/max could be min_t/max_t + if ($line =~ /^\+(?:.*?)\b(min|max)\s*\($Typecast{0,1}($LvalOrFunc)\s*,\s*$Typecast{0,1}($LvalOrFunc)\s*\)/) { + if (defined $2 || defined $8) { + my $call = $1; + my $cast1 = deparenthesize($2); + my $arg1 = $3; + my $cast2 = deparenthesize($8); + my $arg2 = $9; + my $cast; + + if ($cast1 ne "" && $cast2 ne "") { + $cast = "$cast1 or $cast2"; + } elsif ($cast1 ne "") { + $cast = $cast1; + } else { + $cast = $cast2; + } + WARN("$call() should probably be ${call}_t($cast, $arg1, $arg2)\n" . $herecurr); + } + } + # Need a space before open parenthesis after if, while etc if ($line=~/\b(if|while|for|switch)\(/) { ERROR("space required before the open parenthesis '('\n" . $herecurr); -- 2.20.1