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Subject[PATCH 05/23] gpio: sysfs: reduce gpiochip-export locking scope
Date
Reduce scope of sysfs_lock protection during chip export and unexport,
which is only needed to prevent gpiod (re-)exports during chip removal.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/gpio/gpiolib-sysfs.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index da0300224b4a..c433f075f349 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -764,7 +764,6 @@ int gpiochip_export(struct gpio_chip *chip)
return 0;

/* use chip->base for the ID; it's already known to be unique */
- mutex_lock(&sysfs_lock);
dev = device_create_with_groups(&gpio_class, chip->dev, MKDEV(0, 0),
chip, gpiochip_groups,
"gpiochip%d", chip->base);
@@ -772,6 +771,8 @@ int gpiochip_export(struct gpio_chip *chip)
status = PTR_ERR(dev);
else
status = 0;
+
+ mutex_lock(&sysfs_lock);
chip->exported = (status == 0);
mutex_unlock(&sysfs_lock);

@@ -788,17 +789,17 @@ void gpiochip_unexport(struct gpio_chip *chip)
struct gpio_desc *desc;
unsigned int i;

- mutex_lock(&sysfs_lock);
dev = class_find_device(&gpio_class, NULL, chip, match_export);
if (dev) {
put_device(dev);
device_unregister(dev);
/* prevent further gpiod exports */
+ mutex_lock(&sysfs_lock);
chip->exported = false;
+ mutex_unlock(&sysfs_lock);
status = 0;
} else
status = -ENODEV;
- mutex_unlock(&sysfs_lock);

if (status)
chip_dbg(chip, "%s: status %d\n", __func__, status);
--
2.0.5


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