Messages in this thread | | | Date | Fri, 30 May 2014 20:16:59 +0200 | From | Lars-Peter Clausen <> | Subject | Re: [PATCH 2/2] gpio: gpiolib: set gpiochip_remove retval to void |
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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
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