On Mon, 2017-12-11 at 14:43 -0800, Matthew Wilcox wrote:
> - There's no warning for the first paragraph of section 6:
>
> 6) Functions
> ------------
>
> Functions should be short and sweet, and do just one thing. They should
> fit on one or two screenfuls of text (the ISO/ANSI screen size is 80x24,
> as we all know), and do one thing and do that well.
>
> I'm not expecting you to be able to write a perl script that checks
> the first line, but we have way too many 200-plus line functions in
> the kernel. I'd like a warning on anything over 200 lines (a factor
> of 4 over Linus's stated goal).
Perhaps something like this?
(very very lightly tested, more testing appreciated)
---
scripts/checkpatch.pl | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 4306b7616cdd..523aead40b87 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -59,6 +59,7 @@ my $conststructsfile = "$D/const_structs.checkpatch";
my $typedefsfile = "";
my $color = "auto";
my $allow_c99_comments = 1;
+my $max_function_length = 200;
sub help {
my ($exitcode) = @_;
@@ -2202,6 +2203,7 @@ sub process {
my $realcnt = 0;
my $here = '';
my $context_function; #undef'd unless there's a known function
+ my $context_function_linenum;
my $in_comment = 0;
my $comment_edge = 0;
my $first_line = 0;
@@ -2341,6 +2343,7 @@ sub process {
} else {
undef $context_function;
}
+ undef $context_function_linenum;
next;
# track the line number as we move through the hunk, note that
@@ -3200,11 +3203,18 @@ sub process {
if ($sline =~ /^\+\{\s*$/ &&
$prevline =~ /^\+(?:(?:(?:$Storage|$Inline)\s*)*\s*$Type\s*)?($Ident)\(/) {
$context_function = $1;
+ $context_function_linenum = $realline;
}
# check if this appears to be the end of function declaration
if ($sline =~ /^\+\}\s*$/) {
+ if (defined($context_function_linenum) &&
+ ($realline - $context_function_linenum) > $max_function_length) {
+ WARN("LONG_FUNCTION",
+ "'$context_function' function definition is " . ($realline - $context_function_linenum) . " lines, perhaps refactor\n" . $herecurr);
+ }
undef $context_function;
+ undef $context_function_linenum;
}
# check indentation of any line with a bare else
@@ -5983,6 +5993,7 @@ sub process {
defined $stat &&
$stat =~ /^.\s*(?:$Storage\s+)?$Type\s*($Ident)\s*$balanced_parens\s*{/s) {
$context_function = $1;
+ $context_function_linenum = $realline;
# check for multiline function definition with misplaced open brace
my $ok = 0;
--
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