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authorLinus Walleij <linus.walleij@linaro.org>2016-06-15 22:57:38 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-06-24 10:22:06 -0700
commitc6ad700afe337609d7d0ee37be0e469f08e86a1a (patch)
parenta5b62e5e2089996dc87189ea605f9f16e8920528 (diff)
gpio: make sure gpiod_to_irq() returns negative on NULL desc
commit 79bb71bd1d93197ce227fa167b450b633f30a52b upstream. commit 54d77198fdfbc4f0fe11b4252c1d9c97d51a3264 ("gpio: bail out silently on NULL descriptors") doesn't work for gpiod_to_irq(): drivers assume that NULL descriptors will give negative IRQ numbers in return. It has been pointed out that returning 0 is NO_IRQ and that drivers should be amended to treat this as an error, but that is for the longer term: now let us repair the semantics. Cc: Maxime Ripard <maxime.ripard@free-electrons.com> Reported-by: Hans de Goede <hdegoede@redhat.com> Tested-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 8 insertions, 1 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 719d1114f8eb..cf3e71243d6d 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2006,7 +2006,14 @@ int gpiod_to_irq(const struct gpio_desc *desc)
struct gpio_chip *chip;
int offset;
+ /*
+ * Cannot VALIDATE_DESC() here as gpiod_to_irq() consumer semantics
+ * requires this function to not return zero on an invalid descriptor
+ * but rather a negative error number.
+ */
+ if (!desc || !desc->gdev || !desc->gdev->chip)
+ return -EINVAL;
chip = desc->gdev->chip;
offset = gpio_chip_hwgpio(desc);
return chip->to_irq ? chip->to_irq(chip, offset) : -ENXIO;