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Subject[PATCH 18/23] gpio: sysfs: clean up gpiod_export_link locking
Date
Drop unnecessary locking from gpiod_export_link. If the class device has
not already been unregistered, class_find_device returns the ref-counted
class device so there's no need for locking.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
drivers/gpio/gpiolib-sysfs.c | 28 ++++++++--------------------
1 file changed, 8 insertions(+), 20 deletions(-)

diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
index 761e1644cff1..d9265b4609a3 100644
--- a/drivers/gpio/gpiolib-sysfs.c
+++ b/drivers/gpio/gpiolib-sysfs.c
@@ -616,34 +616,22 @@ static int match_export(struct device *dev, const void *desc)
int gpiod_export_link(struct device *dev, const char *name,
struct gpio_desc *desc)
{
- int status = -EINVAL;
+ struct device *cdev;
+ int ret;

if (!desc) {
pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL;
}

- mutex_lock(&sysfs_lock);
-
- if (test_bit(FLAG_EXPORT, &desc->flags)) {
- struct device *tdev;
-
- tdev = class_find_device(&gpio_class, NULL, desc, match_export);
- if (tdev != NULL) {
- status = sysfs_create_link(&dev->kobj, &tdev->kobj,
- name);
- put_device(tdev);
- } else {
- status = -ENODEV;
- }
- }
-
- mutex_unlock(&sysfs_lock);
+ cdev = class_find_device(&gpio_class, NULL, desc, match_export);
+ if (!cdev)
+ return -ENODEV;

- if (status)
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+ ret = sysfs_create_link(&dev->kobj, &cdev->kobj, name);
+ put_device(cdev);

- return status;
+ return ret;
}
EXPORT_SYMBOL_GPL(gpiod_export_link);

--
2.0.5


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