diff options
| -rw-r--r-- | drivers/base/class.c | 25 | ||||
| -rw-r--r-- | drivers/gpio/gpiolib-sysfs.c | 4 | ||||
| -rw-r--r-- | include/linux/device/class.h | 1 |
3 files changed, 28 insertions, 2 deletions
diff --git a/drivers/base/class.c b/drivers/base/class.c index 68a6f9b56d19..a8a1bf976290 100644 --- a/drivers/base/class.c +++ b/drivers/base/class.c @@ -634,6 +634,31 @@ void class_compat_remove_link(struct class_compat *cls, struct device *dev, } EXPORT_SYMBOL_GPL(class_compat_remove_link); +/** + * class_is_registered - determine if at this moment in time, a class is + * registered in the driver core or not. + * @class: the class to check + * + * Returns a boolean to state if the class is registered in the driver core + * or not. Note that the value could switch right after this call is made, + * so only use this in places where you "know" it is safe to do so (usually + * to determine if the specific class has been registered yet or not). + * + * Be careful in using this. + */ +bool class_is_registered(const struct class *class) +{ + struct subsys_private *sp = class_to_subsys(class); + bool is_initialized = false; + + if (sp) { + is_initialized = true; + subsys_put(sp); + } + return is_initialized; +} +EXPORT_SYMBOL_GPL(class_is_registered); + int __init classes_init(void) { class_kset = kset_create_and_add("class", NULL, NULL); diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index a895915affa5..1a9b21731cc9 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -554,7 +554,7 @@ int gpiod_export(struct gpio_desc *desc, bool direction_may_change) int offset; /* can't export until sysfs is available ... */ - if (!gpio_class.p) { + if (!class_is_registered(&gpio_class)) { pr_debug("%s: called too early!\n", __func__); return -ENOENT; } @@ -728,7 +728,7 @@ int gpiochip_sysfs_register(struct gpio_device *gdev) * register later, in gpiolib_sysfs_init() ... here we just * verify that _some_ field of gpio_class got initialized. */ - if (!gpio_class.p) + if (!class_is_registered(&gpio_class)) return 0; /* diff --git a/include/linux/device/class.h b/include/linux/device/class.h index b53728ca56fb..9cb5db0588c8 100644 --- a/include/linux/device/class.h +++ b/include/linux/device/class.h @@ -84,6 +84,7 @@ extern struct kobject *sysfs_dev_block_kobj; int __must_check class_register(struct class *class); void class_unregister(const struct class *class); +bool class_is_registered(const struct class *class); struct class_compat; struct class_compat *class_compat_register(const char *name); |