On Fri 2019-08-30 18:08:20, Andy Shevchenko wrote:
> sscanf() is a heavy one and moreover requires additional boundary checks.
> Convert driver to use kstrtox() and replace kstrtoul() by kstrtobool()
> in gpio_trig_inverted_store().
>
> While here, check the desired brightness against maximum defined for
> a certain LED.
One change per patch, please.
Because this one will not end well.
> @@ -60,10 +60,10 @@ static ssize_t gpio_trig_brightness_store(struct device *dev,
> unsigned desired_brightness;
> int ret;
>
> - ret = sscanf(buf, "%u", &desired_brightness);
> - if (ret < 1 || desired_brightness > 255) {
> + ret = kstrtouint(buf, 10, &desired_brightness);
> + if (ret || desired_brightness > gpio_data->led->max_brightness) {
> dev_err(dev, "invalid value\n");
> - return -EINVAL;
> + return ret ? ret : -EINVAL;
> }
We have people writing 255 into brightness, because that's what we
used to do even for on/off LEDS. It is expected to work even for leds
with max_brightness of 1.
So... we want to saturate here, not return -EINVAL. (And we will
eventually want to switch on/off leds to max_brightness = 1...)
> @@ -86,16 +86,13 @@ static ssize_t gpio_trig_inverted_store(struct device *dev,
> {
> struct led_classdev *led = led_trigger_get_led(dev);
> struct gpio_trig_data *gpio_data = led_trigger_get_drvdata(dev);
> - unsigned long inverted;
> + bool inverted;
> int ret;
>
> - ret = kstrtoul(buf, 10, &inverted);
> - if (ret < 0)
> + ret = kstrtobool(buf, &inverted);
> + if (ret)
> return ret;
>
> - if (inverted > 1)
> - return -EINVAL;
> -
> gpio_data->inverted = inverted;
>
> /* After inverting, we need to update the LED. */
So, this accepted 0/1. Now it also accepts true false and many other pairs.
Which... might be ok. But probably should be separated.
Best regards,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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