gpiolib: improve overlap check of range of gpio (ef7c7553) · Commits · 戴 / test

drivers/gpio/gpiolib.c

+36 −19

Original line number	Diff line number	Diff line
		@@ -182,7 +182,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);

		/*
		* Add a new chip to the global chips list, keeping the list of chips sorted
		* by base order.
		* by range(means [base, base + ngpio - 1]) order.
		*
		* Return -EBUSY if the new chip overlaps with some other chip's integer
		* space.
		@@ -190,31 +190,48 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
		static int gpiochip_add_to_list(struct gpio_chip *chip)
		{
		struct list_head *pos;
		struct gpio_chip *_chip;
		int err = 0;
		struct gpio_chip *iterator;
		struct gpio_chip *previous = NULL;

		if (list_empty(&gpio_chips)) {
		pos = gpio_chips.next;
		goto found;
		}

		/* find where to insert our chip */
		list_for_each(pos, &gpio_chips) {
		_chip = list_entry(pos, struct gpio_chip, list);
		/* shall we insert before _chip? */
		if (_chip->base >= chip->base + chip->ngpio)
		break;
		iterator = list_entry(pos, struct gpio_chip, list);
		if (iterator->base >= chip->base + chip->ngpio) {
		/*
		* Iterator is the first GPIO chip so there is no
		* previous one
		*/
		if (previous == NULL) {
		goto found;
		} else {
		/*
		* We found a valid range(means
		* [base, base + ngpio - 1]) between previous
		* and iterator chip.
		*/
		if (previous->base + previous->ngpio
		<= chip->base)
		goto found;
		}
		}
		previous = iterator;
		}

		/* are we stepping on the chip right before? */
		if (pos != &gpio_chips && pos->prev != &gpio_chips) {
		_chip = list_entry(pos->prev, struct gpio_chip, list);
		if (_chip->base + _chip->ngpio > chip->base) {
		/* We are beyond the last chip in the list */
		if (iterator->base + iterator->ngpio <= chip->base)
		goto found;

		dev_err(chip->parent,
		"GPIO integer space overlap, cannot add chip\n");
		err = -EBUSY;
		}
		}
		return -EBUSY;

		if (!err)
		found:
		list_add_tail(&chip->list, pos);

		return err;
		return 0;
		}

		/**

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