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Date:   Fri, 31 May 2019 10:44:38 +0200
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Subject: Re: [PATCH v2] checkpatch.pl: Warn on duplicate sysctl local variable
To:     Joe Perches <joe@perches.com>, linux-kernel@vger.kernel.org,
        Andy Whitcroft <apw@canonical.com>
CC:     Kees Cook <keescook@chromium.org>,
        Aaron Tomlin <atomlin@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>
From:   Matteo Croce <mcroce@redhat.com>
Message-ID: <B6174D2A-C9E8-438D-A042-C39CAAA35728@redhat.com>
Sender: linux-kernel-owner@vger.kernel.org
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On May 31, 2019 5:06:58 AM GMT+02:00, Joe Perches <joe@perches.com> wrote:
> On Fri, 2019-05-31 at 03:12 +0200, Matteo Croce wrote:
> > Commit 6a33853c5773 ("proc/sysctl: add shared variables for range
> check")
> > adds some shared const variables to be used instead of a local copy
> in
> > each source file.
> > Warn when a chunk duplicates one of these values in a ctl_table
> struct:
> > 
> >     $ scripts/checkpatch.pl 0001-test-commit.patch
> >     WARNING: duplicated sysctl range checking value 'zero', consider
> using the shared one in include/linux/sysctl.h
> >     #27: FILE: arch/arm/kernel/isa.c:48:
> >     +               .extra1         = &zero,
> > 
> >     WARNING: duplicated sysctl range checking value 'int_max',
> consider using the shared one in include/linux/sysctl.h
> >     #28: FILE: arch/arm/kernel/isa.c:49:
> >     +               .extra2         = &int_max,
> > 
> >     total: 0 errors, 2 warnings, 14 lines checked
> > 
> > Signed-off-by: Matteo Croce <mcroce@redhat.com>
> > ---
> >  scripts/checkpatch.pl | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> > index 342c7c781ba5..629c31435487 100755
> > --- a/scripts/checkpatch.pl
> > +++ b/scripts/checkpatch.pl
> > @@ -6639,6 +6639,12 @@ sub process {
> >  				     "unknown module license " . $extracted_string . "\n" .
> $herecurr);
> >  			}
> >  		}
> > +
> > +# check for sysctl duplicate constants
> > +		if ($line =~ /\.extra[12]\s*=\s*&(zero|one|int_max|max_int)\b/) {
> 
> why max_int, there isn't a single use of it in the kernel ?

Because you can never know how a local variabile will be called.
I wanted to add intmax and maxint too, bit it seemed too much.

Bye,
-- 
Matteo Croce
per aspera ad upstream