Although gpiod_get_direction() can be considered side-effect free for
consumers, its internals involve setting or clearing bits in the
affected GPIO descriptor, for which we need to force-cast the const
descriptor parameter. This could lead to incorrect behavior is the
compiler decide to optimize here, so remove this const parameter. The
intent is to make gpiod_get_direction() private anyway, so it does not
really matter.
Reported-by: Uwe Kleine-König <u.kleine-koe...@pengutronix.de>
Signed-off-by: Alexandre Courbot <acour...@nvidia.com>
---
drivers/gpio/gpiolib-sysfs.c | 2 +-
drivers/gpio/gpiolib.c | 8 +++-----
include/linux/gpio/consumer.h | 2 +-
3 files changed, 5 insertions(+), 7 deletions(-)
diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 781fbed00fc3..2ac1800b58bb 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -41,7 +41,7 @@ static DEFINE_MUTEX(sysfs_lock);
static ssize_t gpio_direction_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- const struct gpio_desc *desc = dev_get_drvdata(dev);
+ struct gpio_desc *desc = dev_get_drvdata(dev);
ssize_t status;
mutex_lock(&sysfs_lock);
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 5619922ebf44..0b271ef87c09 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -148,7 +148,7 @@ static int gpiochip_find_base(int ngpio)
*
* This function may sleep if gpiod_cansleep() is true.
*/
-int gpiod_get_direction(const struct gpio_desc *desc)
+int gpiod_get_direction(struct gpio_desc *desc)
{
struct gpio_chip *chip;
unsigned offset;
@@ -164,13 +164,11 @@ int gpiod_get_direction(const struct gpio_desc *desc)
if (status > 0) {
/* GPIOF_DIR_IN, or other positive */
status = 1;
- /* FLAG_IS_OUT is just a cache of the result of get_direction(),
- * so it does not affect constness per se */
- clear_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
+ clear_bit(FLAG_IS_OUT, &desc->flags);
}
if (status == 0) {
/* GPIOF_DIR_OUT */
- set_bit(FLAG_IS_OUT, &((struct gpio_desc *)desc)->flags);
+ set_bit(FLAG_IS_OUT, &desc->flags);
}
return status;
}
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 83c0a61c605d..d54d158ca327 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -66,7 +66,7 @@ __devm_gpiod_get_index_optional(struct device *dev, const
char *con_id,
unsigned int index, enum gpiod_flags flags);
void devm_gpiod_put(struct device *dev, struct gpio_desc *desc);
-int gpiod_get_direction(const struct gpio_desc *desc);
+int gpiod_get_direction(struct gpio_desc *desc);
int gpiod_direction_input(struct gpio_desc *desc);
int gpiod_direction_output(struct gpio_desc *desc, int value);
int gpiod_direction_output_raw(struct gpio_desc *desc, int value);
--
2.1.3
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