From: Kent Gibson <warthog618@gmail.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH v4 12/13] gpiolib: add new ioctl() for monitoring changes in line info
Date: Tue, 9 Jun 2020 08:23:46 +0800 [thread overview]
Message-ID: <20200609002346.GA6042@sol> (raw)
In-Reply-To: <20191224120709.18247-13-brgl@bgdev.pl>
On Tue, Dec 24, 2019 at 01:07:08PM +0100, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
>
[snip!]
> +static int lineinfo_changed_notify(struct notifier_block *nb,
> + unsigned long action, void *data)
> +{
> + struct gpio_chardev_data *priv = to_gpio_chardev_data(nb);
> + struct gpioline_info_changed chg;
> + struct gpio_desc *desc = data;
> + int ret;
> +
> + if (!test_bit(desc_to_gpio(desc), priv->watched_lines))
> + return NOTIFY_DONE;
> +
> + memset(&chg, 0, sizeof(chg));
> + chg.info.line_offset = gpio_chip_hwgpio(desc);
> + chg.event_type = action;
> + chg.timestamp = ktime_get_real_ns();
> + gpio_desc_to_lineinfo(desc, &chg.info);
> +
Is this call legal? It can sleep - in fact you recently changed that
very function to move a mutex call outside of a spinlock protected section.
Here it is being called within an RCU lock, as lineinfo_changed_notify
is at the end of an atomic_notifier_call_chain.
I was looking at adding a chg.seqno here and considering what level of
locking would be appropriate for the source counter when I noticed that
call. Hopefully I'm missing something.
Cheers,
Kent.
next prev parent reply other threads:[~2020-06-09 0:24 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-24 12:06 [PATCH v4 00/13] gpiolib: add an ioctl() for monitoring line status changes Bartosz Golaszewski
2019-12-24 12:06 ` [PATCH v4 01/13] gpiolib: use 'unsigned int' instead of 'unsigned' in gpio_set_config() Bartosz Golaszewski
2020-01-07 10:02 ` Linus Walleij
2019-12-24 12:06 ` [PATCH v4 02/13] gpiolib: have a single place of calling set_config() Bartosz Golaszewski
2020-01-07 10:02 ` Linus Walleij
2020-01-20 8:44 ` Geert Uytterhoeven
2020-01-20 9:54 ` Andy Shevchenko
2020-01-23 10:16 ` Bartosz Golaszewski
2020-02-01 19:52 ` Guenter Roeck
2020-02-03 11:04 ` Bartosz Golaszewski
2019-12-24 12:06 ` [PATCH v4 03/13] gpiolib: convert the type of hwnum to unsigned int in gpiochip_get_desc() Bartosz Golaszewski
2020-01-07 10:03 ` Linus Walleij
2019-12-24 12:07 ` [PATCH v4 04/13] gpiolib: use gpiochip_get_desc() in linehandle_create() Bartosz Golaszewski
2020-01-07 10:04 ` Linus Walleij
2019-12-24 12:07 ` [PATCH v4 05/13] gpiolib: use gpiochip_get_desc() in lineevent_create() Bartosz Golaszewski
2020-01-07 10:04 ` Linus Walleij
2019-12-24 12:07 ` [PATCH v4 06/13] gpiolib: use gpiochip_get_desc() in gpio_ioctl() Bartosz Golaszewski
2020-01-07 10:04 ` Linus Walleij
2019-12-24 12:07 ` [PATCH v4 07/13] kfifo: provide noirqsave variants of spinlocked in and out helpers Bartosz Golaszewski
2019-12-24 12:07 ` [PATCH v4 08/13] kfifo: provide kfifo_is_empty_spinlocked() Bartosz Golaszewski
2019-12-24 12:07 ` [PATCH v4 09/13] gpiolib: rework the locking mechanism for lineevent kfifo Bartosz Golaszewski
2020-01-08 11:06 ` Andy Shevchenko
2019-12-24 12:07 ` [PATCH v4 10/13] gpiolib: emit a debug message when adding events to a full kfifo Bartosz Golaszewski
2019-12-24 12:07 ` [PATCH v4 11/13] gpiolib: provide a dedicated function for setting lineinfo Bartosz Golaszewski
2020-01-08 12:41 ` Andy Shevchenko
2019-12-24 12:07 ` [PATCH v4 12/13] gpiolib: add new ioctl() for monitoring changes in line info Bartosz Golaszewski
2020-01-08 12:46 ` Andy Shevchenko
2020-01-08 16:55 ` Bartosz Golaszewski
2020-06-09 0:23 ` Kent Gibson [this message]
2020-06-09 7:58 ` Bartosz Golaszewski
2019-12-24 12:07 ` [PATCH v4 13/13] tools: gpio: implement gpio-watch Bartosz Golaszewski
2020-01-08 12:47 ` Andy Shevchenko
2020-01-07 10:07 ` [PATCH v4 00/13] gpiolib: add an ioctl() for monitoring line status changes Linus Walleij
2020-01-07 10:38 ` Bartosz Golaszewski
2020-01-07 12:50 ` Linus Walleij
2020-01-07 13:15 ` Stefani Seibold
2020-01-07 14:44 ` Andy Shevchenko
2020-01-07 14:45 ` Andy Shevchenko
2020-01-07 15:19 ` Bartosz Golaszewski
2020-01-07 15:58 ` Andy Shevchenko
2020-01-07 16:51 ` Bartosz Golaszewski
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=20200609002346.GA6042@sol \
--to=warthog618@gmail.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=bgolaszewski@baylibre.com \
--cc=brgl@bgdev.pl \
--cc=gregkh@linuxfoundation.org \
--cc=linus.walleij@linaro.org \
--cc=linux-gpio@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.