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
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