Re: [PATCH] checkpatch: warn about using CONFIG_EXPERIMENTAL

From: Kees Cook
Date: Mon Nov 12 2012 - 18:11:36 EST


On Mon, Nov 12, 2012 at 3:06 PM, Joe Perches <joe@xxxxxxxxxxx> wrote:
> On Mon, 2012-11-12 at 14:50 -0800, Kees Cook wrote:
>> This config item has not carried much meaning for a while now and is
>> almost always enabled by default. As agreed during the Linux kernel
>> summit, it is being removed. This will discourage future addition of
>> CONFIG_EXPERIMENTAL while it is being phased out.
>
> You should also cc Andrew Morton (cc'd)
>
>> Cc: Andy Whitcroft <apw@xxxxxxxxxxxxx>
>> Cc: Joe Perches <joe@xxxxxxxxxxx>
>> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
>> ---
>> scripts/checkpatch.pl | 17 +++++++++++++++++
>> 1 file changed, 17 insertions(+)
>>
>> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
>> index f18750e..41e364b 100755
>> --- a/scripts/checkpatch.pl
>> +++ b/scripts/checkpatch.pl
>> @@ -1757,6 +1757,15 @@ sub process {
>> #print "is_start<$is_start> is_end<$is_end> length<$length>\n";
>> }
>>
>> +# discourage the addition of CONFIG_EXPERIMENTAL in Kconfig.
>> + if ($realfile =~ /Kconfig/ &&
>> + $line =~ /.\s*depends on\s+.*\bEXPERIMENTAL\b/) {
>
> This is after the deleted lines check so this won't trigger
> on deleted lines.

Correct -- I don't want to trigger on deleted lines. That's what we
want to see in patches. :)

>> + WARN("CONFIG_EXPERIMENTAL",
>> + "Use of CONFIG_EXPERIMENTAL is deprecated. " +
>> + "For alternatives, see " +
>> + "https://lkml.org/lkml/2012/10/23/580\n";);
>
> I'd much prefer this be on a single line and not using the +
> string operator as that style is not currently used in checkpatch.

Hah. Okay. We should exclude checkpatch.pl from the 80 character check
it warns about. ;)

>> + }
>> +
>> if (($realfile =~ /Makefile.*/ || $realfile =~ /Kbuild.*/) &&
>> ($line =~ /\+(EXTRA_[A-Z]+FLAGS).*/)) {
>> my $flag = $1;
>> @@ -1912,6 +1921,14 @@ sub process {
>> # check we are in a valid C source file if not then ignore this hunk
>> next if ($realfile !~ /\.(h|c)$/);
>>
>> +# discourage the addition of CONFIG_EXPERIMENTAL in #if(def).
>> + if ($line =~ /^\+\s*\#\s*if.*\bCONFIG_EXPERIMENTAL\b/) {
>
> Same as previous reply just a few minutes ago
>
> There are many config uses like:
> #if defined(CONFIG_FOO)
> and
> #if defined CONFIG_FOO || defined CONFIG_BAR

Right, this will catch those. "if.*" above

> so I think any line that has this specific config option is suspect.
>> + WARN("CONFIG_EXPERIMENTAL",
>> + "Use of CONFIG_EXPERIMENTAL is deprecated. " +
>> + "For alternatives, see " +
>> + "https://lkml.org/lkml/2012/10/23/580\n";);
>> + }
>
>
>

Thanks!

-Kees

--
Kees Cook
Chrome OS Security
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