diff options
Diffstat (limited to 'drivers/base/core.c')
| -rw-r--r-- | drivers/base/core.c | 36 |
1 files changed, 27 insertions, 9 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index d021c98605b..8c2cc2648f5 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -523,11 +523,16 @@ static void klist_children_put(struct klist_node *n) * device_initialize - init device structure. * @dev: device. * - * This prepares the device for use by other layers, - * including adding it to the device hierarchy. + * This prepares the device for use by other layers by initializing + * its fields. * It is the first half of device_register(), if called by - * that, though it can also be called separately, so one - * may use @dev's fields (e.g. the refcount). + * that function, though it can also be called separately, so one + * may use @dev's fields. In particular, get_device()/put_device() + * may be used for reference counting of @dev after calling this + * function. + * + * NOTE: Use put_device() to give up your reference instead of freeing + * @dev directly once you have called this function. */ void device_initialize(struct device *dev) { @@ -536,7 +541,6 @@ void device_initialize(struct device *dev) klist_init(&dev->klist_children, klist_children_get, klist_children_put); INIT_LIST_HEAD(&dev->dma_pools); - INIT_LIST_HEAD(&dev->node); init_MUTEX(&dev->sem); spin_lock_init(&dev->devres_lock); INIT_LIST_HEAD(&dev->devres_head); @@ -836,9 +840,13 @@ static void device_remove_sys_dev_entry(struct device *dev) * This is part 2 of device_register(), though may be called * separately _iff_ device_initialize() has been called separately. * - * This adds it to the kobject hierarchy via kobject_add(), adds it + * This adds @dev to the kobject hierarchy via kobject_add(), adds it * to the global and sibling lists for the device, then * adds it to the other relevant subsystems of the driver model. + * + * NOTE: _Never_ directly free @dev after calling this function, even + * if it returned an error! Always use put_device() to give up your + * reference instead. */ int device_add(struct device *dev) { @@ -916,7 +924,8 @@ int device_add(struct device *dev) if (dev->class) { mutex_lock(&dev->class->p->class_mutex); /* tie the class to the device */ - list_add_tail(&dev->node, &dev->class->p->class_devices); + klist_add_tail(&dev->knode_class, + &dev->class->p->class_devices); /* notify any interfaces that the device is here */ list_for_each_entry(class_intf, @@ -965,6 +974,10 @@ done: * I.e. you should only call the two helpers separately if * have a clearly defined need to use and refcount the device * before it is added to the hierarchy. + * + * NOTE: _Never_ directly free @dev after calling this function, even + * if it returned an error! Always use put_device() to give up the + * reference initialized in this function instead. */ int device_register(struct device *dev) { @@ -1032,7 +1045,7 @@ void device_del(struct device *dev) if (class_intf->remove_dev) class_intf->remove_dev(dev, class_intf); /* remove the device from the class list */ - list_del_init(&dev->node); + klist_del(&dev->knode_class); mutex_unlock(&dev->class->p->class_mutex); } device_remove_file(dev, &uevent_attr); @@ -1243,7 +1256,7 @@ struct device *device_create_vargs(struct class *class, struct device *parent, return dev; error: - kfree(dev); + put_device(dev); return ERR_PTR(retval); } EXPORT_SYMBOL_GPL(device_create_vargs); @@ -1314,6 +1327,11 @@ EXPORT_SYMBOL_GPL(device_destroy); * device_rename - renames a device * @dev: the pointer to the struct device to be renamed * @new_name: the new name of the device + * + * It is the responsibility of the caller to provide mutual + * exclusion between two different calls of device_rename + * on the same device to ensure that new_name is valid and + * won't conflict with other devices. */ int device_rename(struct device *dev, char *new_name) { |