From: Alexandre Courbot <acourbot@nvidia.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Arnd Bergmann <arnd@arndb.de>,
linux-arch <linux-arch@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/9] gpiolib: use gpio_chips list in sysfs ops
Date: Sat, 9 Feb 2013 22:53:22 +0900 [thread overview]
Message-ID: <CAAVeFuLW5pP=Kk7wh63eNAuycvEcXV1op6GkXyZwK85Gqz+DJQ@mail.gmail.com> (raw)
In-Reply-To: <20130209093753.654C53E2C59@localhost>
On Sat, Feb 9, 2013 at 6:37 PM, Grant Likely <grant.likely@secretlab.ca> wrote:
> However, this code is incorrect (it was incorrect before you touched it,
> so not your fault). Moving it to a list makes it a lot worse though
> because it introduces the possibility of dereferencing an invalid
> pointer. The hooks need to grab the spinlock before parsing the list.
>
> I've got a patch which I'll post. I'd appreciate it if you can test
> also.
>
> In actual fact, I'd like to replace the spinlock with a mutex, but that
> requires some auditing to make sure there aren't any users from an
> atomic context.
I thought about doing that as well actually, but left it for later. It
looks safe at first sight, but as you mention we cannot exclude a few
users will break as a consequence of such a switch.
In any case, I plan to give it a try once that big chunk is merged.
Alex.
next prev parent reply other threads:[~2013-02-09 13:53 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-02 16:29 [PATCH 0/9] gpiolib: remove gpio_desc[] static array Alexandre Courbot
2013-02-02 16:29 ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 1/9] gpiolib: link all gpio_chips using a list Alexandre Courbot
2013-02-05 17:00 ` Linus Walleij
2013-02-09 9:20 ` Grant Likely
2013-02-02 16:29 ` [PATCH 2/9] gpiolib: use gpio_chips list in gpiolib_sysfs_init Alexandre Courbot
2013-02-05 17:04 ` Linus Walleij
2013-02-09 9:22 ` Grant Likely
2013-02-02 16:29 ` [PATCH 3/9] gpiolib: use gpio_chips list in gpiochip_find Alexandre Courbot
2013-02-05 17:05 ` Linus Walleij
2013-02-09 9:25 ` Grant Likely
2013-02-02 16:29 ` [PATCH 4/9] gpiolib: use gpio_chips list in sysfs ops Alexandre Courbot
2013-02-05 17:15 ` Linus Walleij
2013-02-09 9:37 ` Grant Likely
2013-02-09 13:53 ` Alexandre Courbot [this message]
2013-02-02 16:29 ` [PATCH 5/9] gpiolib: use gpio_chips list in gpiochip_find_base Alexandre Courbot
2013-02-05 17:21 ` Linus Walleij
2013-02-06 4:48 ` Alex Courbot
2013-02-09 9:47 ` Grant Likely
2013-02-02 16:29 ` [PATCH 6/9] gpiolib: use descriptors internally Alexandre Courbot
2013-02-05 17:53 ` Linus Walleij
2013-02-07 6:57 ` Alexandre Courbot
2013-02-09 9:17 ` Grant Likely
2013-02-11 14:09 ` Linus Walleij
2013-02-11 15:40 ` Paul Mundt
2013-02-11 17:39 ` Stephen Warren
2013-02-12 12:29 ` Linus Walleij
2013-02-12 15:59 ` Paul Mundt
2013-02-12 17:18 ` Arnd Bergmann
2013-02-09 13:11 ` Grant Likely
2013-02-09 14:15 ` Alexandre Courbot
2013-02-09 13:24 ` Grant Likely
2013-02-09 14:18 ` Alexandre Courbot
2013-02-02 16:29 ` [PATCH 7/9] gpiolib: let gpio_chip reference its descriptors Alexandre Courbot
2013-02-05 18:00 ` Linus Walleij
2013-02-09 13:28 ` Grant Likely
2013-02-02 16:29 ` [PATCH 8/9] gpiolib: use gpio_chips list in gpio_to_desc Alexandre Courbot
2013-02-05 18:01 ` Linus Walleij
2013-02-09 9:58 ` Grant Likely
2013-02-09 14:21 ` Alexandre Courbot
2013-02-09 14:37 ` Grant Likely
2013-02-02 16:29 ` [PATCH 9/9] gpiolib: dynamically allocate descriptors array Alexandre Courbot
2013-02-05 18:02 ` Linus Walleij
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