From: Linus Walleij <linus.walleij@linaro.org>
To: Laura Abbott <labbott@redhat.com>
Cc: Phil Reid <preid@electromag.com.au>,
Kees Cook <keescook@chromium.org>,
Patrice Chotard <patrice.chotard@st.com>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
kernel-hardening@lists.openwall.com
Subject: Re: [PATCHv2 4/4] gpio: Remove VLA from stmpe driver
Date: Tue, 27 Mar 2018 15:41:23 +0200 [thread overview]
Message-ID: <CACRpkdafSd0R1czzw8w7bB8Stbvrx6LoP7tR7BQQnB1RSKQysQ@mail.gmail.com> (raw)
In-Reply-To: <90e40062-cedb-be32-ab17-56136c78dbad@redhat.com>
Hi Laura,
sorry for slow response :/
On Thu, Mar 22, 2018 at 10:43 PM, Laura Abbott <labbott@redhat.com> wrote:
> On 03/18/2018 06:29 PM, Phil Reid wrote:
>>
>> On 16/03/2018 02:00, Laura Abbott wrote:
>>>
>>> The new challenge is to remove VLAs from the kernel
>>> (see https://lkml.org/lkml/2018/3/7/621)
>>>
>>> This patch replaces a VLA with an appropriate call to kmalloc_array.
>>>
>>> Signed-off-by: Laura Abbott <labbott@redhat.com>
>>> ---
>>> v2: Switch to GFP_KERNEL. There was some discussion about if we should
>>> be doing the allocation at all but given a) the allocation is pretty
>>> small and b) we can possibly take a mutex in a called function I think
>>> this is fine.
>>
>>
>> I still think it's a bad idea. It's simple to preallocate the buffer.
>> But it's up to the maintainer.
>>
>
> I'd feel a lot more confident about doing the global buffer with
> guidance from the maintainer. But looking at the platform data, the
> maximum number of GPIOs is 24, or 3 banks. Maybe we should just always
> stack allocate the maximum since it's fairly small.
Either way works fine, global (in the state container struct stmpe_gpio)
or stack allocation for 24 bits.
I guess I am maintainer for this, I can test it at least.
Yours,
Linus Walleij
prev parent reply other threads:[~2018-03-27 13:41 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-15 18:00 [PATCHv2 0/4] VLA removal from the gpio subsystem Laura Abbott
2018-03-15 18:00 ` [PATCHv2 1/4] gpio: Remove VLA from gpiolib Laura Abbott
2018-03-17 15:36 ` kbuild test robot
2018-03-15 18:00 ` [PATCHv2 2/4] gpio: Remove VLA from MAX3191X driver Laura Abbott
2018-03-19 14:38 ` Lukas Wunner
2018-03-15 18:00 ` [PATCHv2 3/4] gpio: Remove VLA from xra1403 driver Laura Abbott
2018-03-15 18:00 ` [PATCHv2 4/4] gpio: Remove VLA from stmpe driver Laura Abbott
2018-03-19 1:29 ` Phil Reid
2018-03-22 21:43 ` Laura Abbott
2018-03-23 1:28 ` Phil Reid
2018-03-27 13:41 ` Linus Walleij [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CACRpkdafSd0R1czzw8w7bB8Stbvrx6LoP7tR7BQQnB1RSKQysQ@mail.gmail.com \
--to=linus.walleij@linaro.org \
--cc=keescook@chromium.org \
--cc=kernel-hardening@lists.openwall.com \
--cc=labbott@redhat.com \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=patrice.chotard@st.com \
--cc=preid@electromag.com.au \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).