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Subject[PATCH] gpiolib: fix bitmap operations related to line event watching
Date
From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

When operating on the bits of watched_lines bitmap, we're using
desc_to_gpio() which returns the GPIO number from the global numberspace.
This leads to all sorts of memory corruptions and invalid behavior. We
should switch to using gpio_chip_hwgpio() instead.

Fixes: 51c1064e82e7 ("gpiolib: add new ioctl() for monitoring changes in line info")
Reported-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
drivers/gpio/gpiolib.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index a5cd1b4abe6f..5cc80f6f79e0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1261,7 +1261,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return -EFAULT;

if (cmd == GPIO_GET_LINEINFO_WATCH_IOCTL)
- set_bit(desc_to_gpio(desc), priv->watched_lines);
+ set_bit(gpio_chip_hwgpio(desc), priv->watched_lines);

return 0;
} else if (cmd == GPIO_GET_LINEHANDLE_IOCTL) {
@@ -1276,7 +1276,7 @@ static long gpio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
if (IS_ERR(desc))
return PTR_ERR(desc);

- clear_bit(desc_to_gpio(desc), priv->watched_lines);
+ clear_bit(gpio_chip_hwgpio(desc), priv->watched_lines);
return 0;
}
return -EINVAL;
@@ -1304,7 +1304,7 @@ static int lineinfo_changed_notify(struct notifier_block *nb,
struct gpio_desc *desc = data;
int ret;

- if (!test_bit(desc_to_gpio(desc), priv->watched_lines))
+ if (!test_bit(gpio_chip_hwgpio(desc), priv->watched_lines))
return NOTIFY_DONE;

memset(&chg, 0, sizeof(chg));
--
2.25.0
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