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Subject: Re: [PATCH 6/7] fs/sysfs/group: make attribute_group pointers const
From:   Joe Perches <joe@perches.com>
To:     Max Kellermann <max.kellermann@ionos.com>,
        Guenter Roeck <linux@roeck-us.net>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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Date:   Mon, 09 Oct 2023 23:48:10 -0700
In-Reply-To: <CAKPOu+8k2x1CucWSzoouts0AfMJk+srJXWWf3iWVOeY+fWkOpQ@mail.gmail.com>
References: <20231009165741.746184-1-max.kellermann@ionos.com>
         <20231009165741.746184-6-max.kellermann@ionos.com>
         <264fa39d-aed6-4a54-a085-107997078f8d@roeck-us.net>
         <CAKPOu+8k2x1CucWSzoouts0AfMJk+srJXWWf3iWVOeY+fWkOpQ@mail.gmail.com>
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On Mon, 2023-10-09 at 22:05 +0200, Max Kellermann wrote:
> On Mon, Oct 9, 2023 at 7:24 PM Guenter Roeck <linux@roeck-us.net> wrote:
> > Also, I don't know why checkpatch is happy with all the
> > 
> >         const struct attribute_group *const*groups;
> > 
> > instead of
> > 
> >         const struct attribute_group *const *groups;
> 
> I found out that checkpatch has no check for this at all; it does
> complain about such lines, but only for local variables. But that
> warning is actually a bug, because this is a check for unary
> operators: it thinks the asterisk is a dereference operator, not a
> pointer declaration, and complains that the unary operator must be
> preceded by a space. Thus warnings on local variable are only correct
> by coincidence, not by design.
> 
> Inside structs or parameters (where my coding style violations can be
> found), it's a different context and thus checkpatch doesn't apply the
> rules for unary operators.

My opinion is that const use in the kernel should almost
always have whitespace before and after it except when
preceded by a open parenthesis or a newline.

$ git grep -wh const -- '*.[ch]' | \
  grep -oP "[ \*\(]?const[ \*]?" | \
  sort | uniq -c | sort -rn
 222438  const 
  83386 const 
  51667 (const 
   2766 *const 
    834 const
    442  const
    343  const*
     88 *const
     37 (const
      4 *const*