Re: [PATCH] gpio: gpiolib: set gpiochip_remove retval to void

From: Alexandre Courbot
Date: Sun May 25 2014 - 03:46:52 EST


On Sat, May 24, 2014 at 2:12 AM, abdoulaye berthe <berthe.ab@xxxxxxxxx> wrote:
> This avoids handling gpiochip remove error in device
> remove handler.

Be aware that at the moment many callers of gpiochip_remove() read its
return value. So applying your patch as-is would break compilation.

This patch should therefore be the last of a series that first
modifies all callers of gpiochip_remove() to ignore its return value,
then neutralizes the function itself.

I am not sure whether the world would really be a better place after
this though. Callers that don't need the return value of
gpiochip_remove() can simply ignore it...

>
> Signed-off-by: abdoulaye berthe <berthe.ab@xxxxxxxxx>
> ---
> drivers/gpio/gpiolib.c | 24 +++++++-----------------
> include/linux/gpio/driver.h | 2 +-
> 2 files changed, 8 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index f48817d..4878980 100644
> --- 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("gpiolib.c: gpiochip is still requested\n");

panic() sounds a little harsh here. Maybe a dev_err() would be enough?

> }
> + for (id = 0; id < chip->ngpio; id++)
> + chip->desc[id].chip = NULL;
>
> + list_del(&chip->list);
> spin_unlock_irqrestore(&gpio_lock, flags);
> -
> - if (status == 0)
> - gpiochip_unexport(chip);
> -
> - return status;
> + gpiochip_unexport(chip);
> }
> EXPORT_SYMBOL_GPL(gpiochip_remove);
>
> diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
> index 1827b43..72ed256 100644
> --- a/include/linux/gpio/driver.h
> +++ b/include/linux/gpio/driver.h
> @@ -138,7 +138,7 @@ extern const char *gpiochip_is_requested(struct gpio_chip *chip,
>
> /* add/remove chips */
> extern int gpiochip_add(struct gpio_chip *chip);
> -extern int __must_check gpiochip_remove(struct gpio_chip *chip);
> +void gpiochip_remove(struct gpio_chip *chip);

"extern" should be preserved here for style consistency.
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