From: Bartosz Golaszewski <brgl@bgdev.pl>
To: Kent Gibson <warthog618@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Linux Kernel Mailing List <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 09:58:16 +0200 [thread overview]
Message-ID: <CAMRc=Mf+xYFaznq+O=wEjb3UyanuH5b3hvOpNx9Jcx+Vm65g7A@mail.gmail.com> (raw)
In-Reply-To: <20200609002346.GA6042@sol>
wt., 9 cze 2020 o 02:23 Kent Gibson <warthog618@gmail.com> napisał(a):
>
> 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.
>
Yeah, this is clearly wrong and lockdep would complain about invalid
wait context. I'm trying to remember why I went for an atomic notifier
chain here though... At first glance it doesn't look like the chain
could be called from atomic context anywhere.
Bart
next prev parent reply other threads:[~2020-06-09 7:58 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
2020-06-09 7:58 ` Bartosz Golaszewski [this message]
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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