Commit 9d846b1a authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpiolib: check the return value of gpio_chip::get_direction() 



As per the API contract - gpio_chip::get_direction() may fail and return
a negative error number. However, we treat it as if it always returned 0
or 1. Check the return value of the callback and propagate the error
number up the stack.

Cc: stable@vger.kernel.org
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-1-12ea88506cb2@linaro.org


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent 0ad2507d

drivers/gpio/gpiolib.c

+29 −15
Original line number Diff line number Diff line
@@ -1057,8 +1057,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 
		desc->gdev = gdev;



		if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) {

			assign_bit(FLAG_IS_OUT,

				   &desc->flags, !gc->get_direction(gc, desc_index));

			ret = gc->get_direction(gc, desc_index);

			if (ret < 0)

				goto err_cleanup_desc_srcu;



			assign_bit(FLAG_IS_OUT, &desc->flags, !ret);

		} else {

			assign_bit(FLAG_IS_OUT,

				   &desc->flags, !gc->direction_input);
@@ -2728,14 +2731,19 @@ int gpiod_direction_input_nonotify(struct gpio_desc *desc) 
	if (guard.gc->direction_input) {

		ret = guard.gc->direction_input(guard.gc,

						gpio_chip_hwgpio(desc));

	} else if (guard.gc->get_direction &&

		  (guard.gc->get_direction(guard.gc,

					   gpio_chip_hwgpio(desc)) != 1)) {

	} else if (guard.gc->get_direction) {

		ret = guard.gc->get_direction(guard.gc,

					      gpio_chip_hwgpio(desc));

		if (ret < 0)

			return ret;



		if (ret != GPIO_LINE_DIRECTION_IN) {

			gpiod_warn(desc,

				   "%s: missing direction_input() operation and line is output\n",

				    __func__);

			return -EIO;

		}

	}

	if (ret == 0) {

		clear_bit(FLAG_IS_OUT, &desc->flags);

		ret = gpio_set_bias(desc);
@@ -2771,13 +2779,19 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) 
						 gpio_chip_hwgpio(desc), val);

	} else {

		/* Check that we are in output mode if we can */

		if (guard.gc->get_direction &&

		    guard.gc->get_direction(guard.gc, gpio_chip_hwgpio(desc))) {

		if (guard.gc->get_direction) {

			ret = guard.gc->get_direction(guard.gc,

						      gpio_chip_hwgpio(desc));

			if (ret < 0)

				return ret;



			if (ret != GPIO_LINE_DIRECTION_OUT) {

				gpiod_warn(desc,

					   "%s: missing direction_output() operation\n",

					   __func__);

				return -EIO;

			}

		}

		/*

		 * If we can't actively set the direction, we are some

		 * output-only chip, so just drive the output as desired.