From: Lars-Peter Clausen <lars@metafoo.de>
To: David Daney <ddaney.cavm@gmail.com>
Cc: platform-driver-x86@vger.kernel.org,
Alexandre Courbot <gnurou@gmail.com>,
patches@opensource.wolfsonmicro.com,
Linux MIPS Mailing List <linux-mips@linux-mips.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Linux-sh list <linux-sh@vger.kernel.org>,
linux-wireless <linux-wireless@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
spear-devel@list.st.com, linux-samsungsoc@vger.kernel.org,
"linux-gpio@vger.kernel.org" <linux-gpio@vger.kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>,
"linux-leds@vger.kernel.org" <linux-leds@vger.kernel.org>,
m@bues.ch,
"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
driverdevel <devel@driverdev.osuosl.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
abdoulaye berthe <berthe.ab@gmail.com>
Subject: Re: [PATCH 2/2] gpio: gpiolib: set gpiochip_remove retval to void
Date: Fri, 30 May 2014 20:16:59 +0200 [thread overview]
Message-ID: <5388CB1B.3090802@metafoo.de> (raw)
In-Reply-To: <5388C0F1.90503@gmail.com>
On 05/30/2014 07:33 PM, David Daney wrote:
> On 05/30/2014 04:39 AM, Geert Uytterhoeven wrote:
>> On Fri, May 30, 2014 at 1:30 PM, abdoulaye berthe <berthe.ab@gmail.com>
>> wrote:
>>> --- a/drivers/gpio/gpiolib.c
>>> +++ b/drivers/gpio/gpiolib.c
>>> @@ -1263,10 +1263,9 @@ static void gpiochip_irqchip_remove(struct
>>> gpio_chip *gpiochip);
>>> *
>>> * A gpio_chip with any GPIOs still requested may not be removed.
>>> */
>>> -int gpiochip_remove(struct gpio_chip *chip)
>>> +void gpiochip_remove(struct gpio_chip *chip)
>>> {
>>> unsigned long flags;
>>> - int status = 0;
>>> unsigned id;
>>>
>>> acpi_gpiochip_remove(chip);
>>> @@ -1278,24 +1277,15 @@ int gpiochip_remove(struct gpio_chip *chip)
>>> of_gpiochip_remove(chip);
>>>
>>> for (id = 0; id < chip->ngpio; id++) {
>>> - if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags)) {
>>> - status = -EBUSY;
>>> - break;
>>> - }
>>> - }
>>> - if (status == 0) {
>>> - for (id = 0; id < chip->ngpio; id++)
>>> - chip->desc[id].chip = NULL;
>>> -
>>> - list_del(&chip->list);
>>> + if (test_bit(FLAG_REQUESTED, &chip->desc[id].flags))
>>> + panic("gpio: removing gpiochip with gpios still
>>> requested\n");
>>
>> panic?
>
> NACK to the patch for this reason. The strongest thing you should do here
> is WARN.
>
> That said, I am not sure why we need this whole patch set in the first place.
Well, what currently happens when you remove a device that is a provider of
a gpio_chip which is still in use, is that the kernel crashes. Probably with
a rather cryptic error message. So this patch doesn't really change the
behavior, but makes it more explicit what is actually wrong. And even if you
replace the panic() by a WARN() it will again just crash slightly later.
This is a design flaw in the GPIO subsystem that needs to be fixed.
- Lars
next prev parent reply other threads:[~2014-05-30 18:37 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-29 21:54 [PATCH] gpio: removes all usage of gpiochip_remove retval abdoulaye berthe
2014-05-29 22:14 ` David Daney
2014-05-29 23:16 ` abdoulaye berthe
2014-05-29 23:40 ` Stephen Rothwell
2014-05-30 11:30 ` [PATCH 1/2] " abdoulaye berthe
2014-05-30 11:30 ` [PATCH 2/2] gpio: gpiolib: set gpiochip_remove retval to void abdoulaye berthe
2014-05-30 11:39 ` Geert Uytterhoeven
2014-05-30 15:48 ` Ralf Baechle
2014-05-30 17:33 ` David Daney
2014-05-30 18:16 ` Lars-Peter Clausen [this message]
2014-05-30 23:29 ` Greg KH
2014-05-31 7:35 ` Lars-Peter Clausen
2014-05-31 12:19 ` Dan Carpenter
2014-06-08 23:18 ` Ben Dooks
2014-06-09 11:29 ` Lars-Peter Clausen
2014-05-29 23:25 ` [PATCH] gpio: removes all usage of gpiochip_remove retval Greg KH
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