Re: [PATCH] lib/string: sysfs_streq works case insensitively

From: Gioh Kim <gi-oh.kim@ionos.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] lib/string: sysfs_streq works case insensitively
Date: Wed, 28 Apr 2021 10:31:37 +0200	[thread overview]
Message-ID: <CAJX1YtaRAgg3oZ6X2cDtj0yASQ27XujDys97vbB0MWnN9vXakQ@mail.gmail.com> (raw)
In-Reply-To: <650dc1b8-d801-2263-2e5c-eb833f2c4534@rasmusvillemoes.dk>

On Wed, Apr 28, 2021 at 9:47 AM Rasmus Villemoes
<linux@rasmusvillemoes.dk> wrote:
>
> On 28/04/2021 09.31, Gioh Kim wrote:
> > On Wed, Apr 28, 2021 at 8:42 AM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote:
> >>
>
> >>
> >> Are you sure it’s good change? Sysfs is used for an ABI and you are opening a can of worms. From me NAK to this change without a very good background description that tells why it is safe to do.
> >
> > https://www.spinics.net/lists/kernel/msg3898123.html
> > My initial idea was making a new function: sysfs_streqcase.
> > Andrew and Greg suggested making sysfs_streq to be case-insensitive.
> > I would like to have a discussion about it.
>
> 1. That information should be in the commit log, not some random
> babbling about case sensitivity of file systems.

I don't think it is a good idea to write who suggested the concept of the patch.

>
> 2. So as Andy says, this is changing ABI for a whole lot of users in one
> go. While it's _probably_ true that nobody would care (because it just
> ends up accepting more strings, not fewer), your motivation seems to be
> to replace uses of strncasecmp() to prevent "disableGARBAGE@#$@#@" to be
> accepted as equivalent to "disable". I.e., those potential new users of
> sysfs_streq() would have their ABI changed towards being less
> permissive. That's a bigger change, with a higher chance of breaking
> something. Do you even know if the maintainers of those drivers would
> accept a switch to a case-insensitive sysfs_streq()?

I don't know what all maintainers would think about the patch.
I thought sending a patch to the mailing list is asking for it, isn't it?
I am asking with this email.

And Andrew and Greg are maintainers.
I am sending this patch because I accepted their feedback.
I don't know other maintainers personally,
so I cannot contact them to ask what they think about my idea before
sending this email.

>
> Sorry, I really think you need a lot stronger motivation for introducing
> either this change or a sysfs_strcaseeq().

I found out a problem of sysfs_streq when I tried to use it for
modules I am working on (RTRS/RNBD).
Then I thought it would be better if there is something like sysfs_streqcase.
That's why I sent the path.
If nobody needs the change, it is ok for me to ignore the patch.

Maybe I misunderstand when I can send a patch to Linux kernel community.
But the only motivation of me is sharing my idea just in case there is
someone who also needs it.
I am sorry if I misunderstand how Linux kernel community works
but I thought I could suggest something good to me.

>
> Rasmus