From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>,
Linus Walleij <linus.walleij@linaro.org>,
Jonathan Corbet <corbet@lwn.net>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Kent Gibson <warthog618@gmail.com>,
linux-gpio <linux-gpio@vger.kernel.org>,
linux-doc <linux-doc@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
ACPI Devel Maling List <linux-acpi@vger.kernel.org>
Subject: Re: [PATCH 03/23] lib: uaccess: provide getline_from_user()
Date: Mon, 7 Sep 2020 13:57:48 +0200 [thread overview]
Message-ID: <CAMpxmJWOSvCr8XthVn46qw=dqwG4cSS00z05XXbTYMOJBnjkkQ@mail.gmail.com> (raw)
In-Reply-To: <20200907114551.GV1891694@smile.fi.intel.com>
On Mon, Sep 7, 2020 at 1:45 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Mon, Sep 07, 2020 at 12:28:05PM +0200, Bartosz Golaszewski wrote:
> > On Mon, Sep 7, 2020 at 12:19 PM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote:
> > >
> > > On Mon, Sep 7, 2020 at 1:05 PM Bartosz Golaszewski
> > > <bgolaszewski@baylibre.com> wrote:
> > > > On Fri, Sep 4, 2020 at 6:35 PM Andy Shevchenko
> > > > <andriy.shevchenko@linux.intel.com> wrote:
> > > > > On Fri, Sep 04, 2020 at 05:45:27PM +0200, Bartosz Golaszewski wrote:
> > > > > > From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> > >
> > > > > Doesn't mm/util.c provides us something like this?
> > > > > strndup_user()?
> > > > >
> > > >
> > > > Yes, there's both strndup_user() as well as strncpy_from_user(). The
> > > > problem is that they rely on the strings being NULL-terminated. This
> > > > is not guaranteed for debugfs file_operations write callbacks. We need
> > > > some helper that takes the minimum of bytes provided by userspace and
> > > > the buffer size and figure out how many bytes to actually copy IMO.
> > >
> > > Wouldn't this [1] approach work?
> > >
> > > [1]: https://elixir.bootlin.com/linux/v5.9-rc3/source/arch/x86/kernel/cpu/mtrr/if.c#L93
> > >
> >
> > Sure, but this is pretty much what I do in getline_from_user(). If
> > anything we should port mtrr_write() to using getline_from_user() once
> > it's available upstream, no?
>
> But you may provide getline_from_user() as inline in the same header where
> strncpy_from_user() is declared. It will be like 3 LOCs?
>
May be more than that. I'll see what I can do.
Bart
next prev parent reply other threads:[~2020-09-07 11:58 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 15:45 [PATCH 00/23] gpio: mockup: support dynamically created and removed chips Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 01/23] lib: cmdline: export next_arg() Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 02/23] lib: string_helpers: provide kfree_strarray() Bartosz Golaszewski
2020-09-04 16:33 ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 03/23] lib: uaccess: provide getline_from_user() Bartosz Golaszewski
2020-09-04 16:35 ` Andy Shevchenko
2020-09-07 10:02 ` Bartosz Golaszewski
2020-09-07 10:18 ` Andy Shevchenko
2020-09-07 10:28 ` Bartosz Golaszewski
2020-09-07 11:45 ` Andy Shevchenko
2020-09-07 11:57 ` Bartosz Golaszewski [this message]
2020-09-04 15:45 ` [PATCH 04/23] gpiolib: generalize devprop_gpiochip_set_names() for device properties Bartosz Golaszewski
2020-09-04 16:38 ` Andy Shevchenko
2020-09-07 10:56 ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 05/23] gpiolib: unexport devprop_gpiochip_set_names() Bartosz Golaszewski
2020-09-04 16:40 ` Andy Shevchenko
2020-09-07 10:53 ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 06/23] gpiolib: switch to simpler IDA interface Bartosz Golaszewski
2020-09-04 16:41 ` Andy Shevchenko
2020-09-07 10:50 ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 07/23] gpio: mockup: drop unneeded includes Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 08/23] gpio: mockup: use pr_fmt() Bartosz Golaszewski
2020-09-04 16:29 ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 09/23] gpio: mockup: use KBUILD_MODNAME Bartosz Golaszewski
2020-09-04 16:30 ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 10/23] gpio: mockup: fix resource leak in error path Bartosz Golaszewski
2020-09-04 17:00 ` Andy Shevchenko
2020-09-07 11:04 ` Bartosz Golaszewski
2020-09-07 11:47 ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 11/23] gpio: mockup: remove the limit on number of dummy chips Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 12/23] gpio: mockup: define a constant for chip label size Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 13/23] gpio: mockup: pass the chip label as device property Bartosz Golaszewski
2020-09-04 16:48 ` Andy Shevchenko
2020-09-07 11:01 ` Bartosz Golaszewski
2020-09-07 11:48 ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 14/23] gpio: mockup: use the generic 'gpio-line-names' property Bartosz Golaszewski
2020-09-04 16:46 ` Andy Shevchenko
2020-09-07 10:58 ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 15/23] gpio: mockup: use dynamic device IDs Bartosz Golaszewski
2020-09-04 16:49 ` Andy Shevchenko
2020-09-07 11:04 ` Bartosz Golaszewski
2020-09-07 11:50 ` Andy Shevchenko
2020-09-07 11:59 ` Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 16/23] gpio: mockup: refactor the module init function Bartosz Golaszewski
2020-09-04 16:50 ` Andy Shevchenko
2020-09-07 11:05 ` Bartosz Golaszewski
2020-09-07 11:51 ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 17/23] gpio: mockup: rename and move around debugfs callbacks Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 18/23] gpio: mockup: require debugfs to build Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 19/23] gpio: mockup: add a symlink for the per-chip debugfs directory Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 20/23] gpio: mockup: add a lock for dummy device list Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 21/23] gpio: mockup: provide a way to delete dummy chips Bartosz Golaszewski
2020-09-04 16:56 ` Andy Shevchenko
2020-09-04 15:45 ` [PATCH 22/23] gpio: mockup: provide a way to create new " Bartosz Golaszewski
2020-09-04 15:45 ` [PATCH 23/23] Documentation: gpio: add documentation for gpio-mockup Bartosz Golaszewski
2020-09-04 16:58 ` Andy Shevchenko
2020-09-05 3:15 ` Randy Dunlap
2020-09-07 9:59 ` Andy Shevchenko
2020-09-07 10:26 ` Bartosz Golaszewski
2020-09-07 11:53 ` Andy Shevchenko
2020-09-07 12:06 ` Bartosz Golaszewski
2020-09-07 12:22 ` Greg Kroah-Hartman
2020-09-07 13:49 ` Bartosz Golaszewski
2020-09-07 14:08 ` Andy Shevchenko
2020-09-07 15:14 ` Bartosz Golaszewski
2020-09-07 15:23 ` Geert Uytterhoeven
2020-09-07 16:08 ` Bartosz Golaszewski
2020-09-08 17:03 ` Bartosz Golaszewski
2020-09-11 12:56 ` Greg Kroah-Hartman
2020-09-11 13:07 ` Bartosz Golaszewski
2020-09-07 12:38 ` Andy Shevchenko
2020-09-07 12:57 ` Bartosz Golaszewski
2020-09-07 13:52 ` Andy Shevchenko
2020-09-07 10:45 ` Bartosz Golaszewski
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