Re: [PATCH v2 2/6] gpio: cdev: prepare gpio_desc_to_lineinfo() for being called from atomic

[Kent Gibson]

On Thu, Oct 10, 2024 at 11:10:23AM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
>
> In order to prepare gpio_desc_to_lineinfo() to being called from atomic
> context, add a new argument - bool atomic - which, if set, indicates
> that no sleeping functions must be called (currently: only
> pinctrl_gpio_can_use_line()).
>
> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> ---
>  drivers/gpio/gpiolib-cdev.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
> index b0050250ac3a..8c48a53b4fa8 100644
> --- a/drivers/gpio/gpiolib-cdev.c
> +++ b/drivers/gpio/gpiolib-cdev.c
> @@ -2361,7 +2361,7 @@ static void gpio_v2_line_info_changed_to_v1(
>  #endif /* CONFIG_GPIO_CDEV_V1 */
>
>  static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
> -				  struct gpio_v2_line_info *info)
> +				  struct gpio_v2_line_info *info, bool atomic)
>  {
>  	unsigned long dflags;
>  	const char *label;
> @@ -2402,9 +2402,13 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc,
>  	    test_bit(FLAG_USED_AS_IRQ, &dflags) ||
>  	    test_bit(FLAG_EXPORT, &dflags) ||
>  	    test_bit(FLAG_SYSFS, &dflags) ||
> -	    !gpiochip_line_is_valid(guard.gc, info->offset) ||
> -	    !pinctrl_gpio_can_use_line(guard.gc, info->offset))
> +	    !gpiochip_line_is_valid(guard.gc, info->offset))
>  		info->flags |= GPIO_V2_LINE_FLAG_USED;
> +
> +	if (!atomic) {
> +		if (!pinctrl_gpio_can_use_line(guard.gc, info->offset))
> +			info->flags |= GPIO_V2_LINE_FLAG_USED;
> +	}
>

Should be else if.

Cheers,
Kent.

>  	if (test_bit(FLAG_IS_OUT, &dflags))
>  		info->flags |= GPIO_V2_LINE_FLAG_OUTPUT;
> @@ -2502,7 +2506,7 @@ static int lineinfo_get_v1(struct gpio_chardev_data *cdev, void __user *ip,
>  			return -EBUSY;
>  	}
>
> -	gpio_desc_to_lineinfo(desc, &lineinfo_v2);
> +	gpio_desc_to_lineinfo(desc, &lineinfo_v2, false);
>  	gpio_v2_line_info_to_v1(&lineinfo_v2, &lineinfo);
>
>  	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
> @@ -2539,7 +2543,7 @@ static int lineinfo_get(struct gpio_chardev_data *cdev, void __user *ip,
>  		if (test_and_set_bit(lineinfo.offset, cdev->watched_lines))
>  			return -EBUSY;
>  	}
> -	gpio_desc_to_lineinfo(desc, &lineinfo);
> +	gpio_desc_to_lineinfo(desc, &lineinfo, false);
>  	supinfo_to_lineinfo(desc, &lineinfo);
>
>  	if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
> @@ -2632,7 +2636,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
>  	memset(&chg, 0, sizeof(chg));
>  	chg.event_type = action;
>  	chg.timestamp_ns = ktime_get_ns();
> -	gpio_desc_to_lineinfo(desc, &chg.info);
> +	gpio_desc_to_lineinfo(desc, &chg.info, false);
>  	supinfo_to_lineinfo(desc, &chg.info);
>
>  	ret = kfifo_in_spinlocked(&cdev->events, &chg, 1, &cdev->wait.lock);
>
> --
> 2.43.0
>