linux-kernel - Re: [PATCH v3 1/2] checkpatch: add Kconfig 'default n' test

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Date:	Mon, 06 Jun 2016 09:43:15 -0700
From:	Joe Perches <joe@...ches.com>
To:	Yingjoe Chen <yingjoe.chen@...iatek.com>,
	Andy Whitcroft <apw@...onical.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org, srv_heupstream@...iatek.com,
	Andi Kleen <ak@...ux.intel.com>,
	Paul Bolle <pebolle@...cali.nl>
Subject: Re: [PATCH v3 1/2] checkpatch: add Kconfig 'default n' test

On Sat, 2016-06-04 at 13:10 +0800, Yingjoe Chen wrote:
> If a Kconfig config option doesn't specify 'default', the default
> will be n. Adding 'default n' is unnecessary.
> Add a test to warn about this.

Is it obvious that a Kconfig has "default n" ?
This seems to work, but is this useful?

> Signed-off-by: Yingjoe Chen <yingjoe.chen@...iatek.com>
> ---
> For this series, rebase to v4.7-rc1 and dropped 'relax Kconfig help text
> line number threshold' patch.
> 
> Let me know what you think. Thanks.
> 
> 
> Change in v3:
> - Rebase to v4.7-rc1
> 
> Change in v2:
> - Change according to Joe Perches' suggesti
> 
>  scripts/checkpatch.pl | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 6750595..f5ce804 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -2683,6 +2683,13 @@ sub process {
>  			     "Use of boolean is deprecated, please use bool instead.\n" . $herecurr);
>  		}
>  
> +# discourage the use of default n
> +		if ($realfile =~ /Kconfig/ &&
> +		    $line =~ /^\+\s*default\s*n\s*(#.*|$)/i) {
> +			WARN("CONFIG_DEFAULT_N",
> +			     "Use of default n is unnecessary, default is n when omitted.\n" . $herecurr);
> +		}
> +
>  		if (($realfile =~ /Makefile.*/ || $realfile =~ /Kbuild.*/) &&
>  		    ($line =~ /\+(EXTRA_[A-Z]+FLAGS).*/)) {
>  			my $flag = $1;