Re: [PATCH 09/10] gpiolib: use gpiochip_dup_line_label() in for_each helpers

Bartosz Golaszewski
2023-11-29T14:43:54Z

On Wed, Nov 29, 2023 at 3:24 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
>
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
>
> Rework for_each_requested_gpio_in_range() to use the new helper to
> retrieve a dynamically allocated copy of the descriptor label and free
> it at the end of each iteration.
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> ---
> include/linux/gpio/driver.h | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
> index 9796a34e2fee..6405f6d454af 100644
> --- a/include/linux/gpio/driver.h
> +++ b/include/linux/gpio/driver.h
> @@ -543,8 +543,10 @@ char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset);
> * @label: label of current GPIO
> */
> #define for_each_requested_gpio_in_range(chip, i, base, size, label) \
> - for (i = 0; i < size; i++) \
> - if ((label = gpiochip_is_requested(chip, base + i)) == NULL) {} else
> + for (i = 0; i < size; i++, kfree(label)) \
> + if ((label = gpiochip_dup_line_label(chip, base + i)) == NULL) {} \
> + else if (IS_ERR(label)) {} \
> + else
>

Ah, cr*p, it will leak if we break out of the loop, why did I think it
was correct?

Any ideas how to handle this one? I was thinking something like:

for (i = 0, char *p __free(kfree) = label; i < size; i++)

would work but it doesn't.

Bart

> /* Iterates over all requested GPIO of the given @chip */
> #define for_each_requested_gpio(chip, i, label) \
> --
> 2.40.1
>