On 10/27/2016 05:29 AM, Kirti Wankhede wrote:
> +int mdev_register_device(struct device *dev, const struct parent_ops *ops)
> +{
> + int ret;
> + struct parent_device *parent;
> +
> + /* check for mandatory ops */
> + if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
> + return -EINVAL;
> +
> + dev = get_device(dev);
> + if (!dev)
> + return -EINVAL;
> +
> + mutex_lock(&parent_list_lock);
> +
> + /* Check for duplicate */
> + parent = __find_parent_device(dev);
> + if (parent) {
> + ret = -EEXIST;
> + goto add_dev_err;
> + }
> +
> + parent = kzalloc(sizeof(*parent), GFP_KERNEL);
> + if (!parent) {
> + ret = -ENOMEM;
> + goto add_dev_err;
> + }
> +
> + kref_init(&parent->ref);
> + mutex_init(&parent->lock);
> +
> + parent->dev = dev;
> + parent->ops = ops;
> +
> + ret = parent_create_sysfs_files(parent);
> + if (ret) {
> + mutex_unlock(&parent_list_lock);
> + mdev_put_parent(parent);
> + return ret;
> + }
> +
> + ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
> + if (ret)
> + dev_warn(dev, "Failed to create compatibility class link\n");
> +
Hi Kirti,
Like I replied to previous version:
http://www.spinics.net/lists/kvm/msg139331.html
You can always check if mdev_bus_compat_class already registered
here, and register it if not yet. Same logic should be adopted to
mdev_init.
Current implementation will simply panic if configured as builtin,
which is rare but far from impossible.
--
Thanks,
Jike
> + list_add(&parent->next, &parent_list);
> + mutex_unlock(&parent_list_lock);
> +
> + dev_info(dev, "MDEV: Registered\n");
> + return 0;
> +
> +add_dev_err:
> + mutex_unlock(&parent_list_lock);
> + put_device(dev);
> + return ret;
> +}
> +EXPORT_SYMBOL(mdev_register_device);
> +
> +/*
> + * mdev_unregister_device : Unregister a parent device
> + * @dev: device structure representing parent device.
> + *
> + * Remove device from list of registered parent devices. Give a chance to free
> + * existing mediated devices for given device.
> + */
> +
> +void mdev_unregister_device(struct device *dev)
> +{
> + struct parent_device *parent;
> + bool force_remove = true;
> +
> + mutex_lock(&parent_list_lock);
> + parent = __find_parent_device(dev);
> +
> + if (!parent) {
> + mutex_unlock(&parent_list_lock);
> + return;
> + }
> + dev_info(dev, "MDEV: Unregistering\n");
> +
> + list_del(&parent->next);
> + class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
> +
> + device_for_each_child(dev, (void *)&force_remove,
> + mdev_device_remove_cb);
> +
> + parent_remove_sysfs_files(parent);
> +
> + mutex_unlock(&parent_list_lock);
> + mdev_put_parent(parent);
> +}
> +EXPORT_SYMBOL(mdev_unregister_device);
> +
> +static void mdev_device_release(struct device *dev)
> +{
> + struct mdev_device *mdev = to_mdev_device(dev);
> +
> + dev_dbg(&mdev->dev, "MDEV: destroying\n");
> + kfree(mdev);
> +}
> +
> +int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid)
> +{
> + int ret;
> + struct mdev_device *mdev;
> + struct parent_device *parent;
> + struct mdev_type *type = to_mdev_type(kobj);
> +
> + parent = mdev_get_parent(type->parent);
> + if (!parent)
> + return -EINVAL;
> +
> + mutex_lock(&parent->lock);
> +
> + /* Check for duplicate */
> + if (mdev_device_exist(parent, uuid)) {
> + ret = -EEXIST;
> + goto create_err;
> + }
> +
> + mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
> + if (!mdev) {
> + ret = -ENOMEM;
> + goto create_err;
> + }
> +
> + memcpy(&mdev->uuid, &uuid, sizeof(uuid_le));
> + mdev->parent = parent;
> + kref_init(&mdev->ref);
> +
> + mdev->dev.parent = dev;
> + mdev->dev.bus = &mdev_bus_type;
> + mdev->dev.release = mdev_device_release;
> + dev_set_name(&mdev->dev, "%pUl", uuid.b);
> +
> + ret = device_register(&mdev->dev);
> + if (ret) {
> + put_device(&mdev->dev);
> + goto create_err;
> + }
> +
> + ret = mdev_device_create_ops(kobj, mdev);
> + if (ret)
> + goto create_failed;
> +
> + ret = mdev_create_sysfs_files(&mdev->dev, type);
> + if (ret) {
> + mdev_device_remove_ops(mdev, true);
> + goto create_failed;
> + }
> +
> + mdev->type_kobj = kobj;
> + dev_dbg(&mdev->dev, "MDEV: created\n");
> +
> + mutex_unlock(&parent->lock);
> + return ret;
> +
> +create_failed:
> + device_unregister(&mdev->dev);
> +
> +create_err:
> + mutex_unlock(&parent->lock);
> + mdev_put_parent(parent);
> + return ret;
> +}
> +
> +int mdev_device_remove(struct device *dev, bool force_remove)
> +{
> + struct mdev_device *mdev;
> + struct parent_device *parent;
> + struct mdev_type *type;
> + int ret;
> +
> + mdev = to_mdev_device(dev);
> + type = to_mdev_type(mdev->type_kobj);
> + parent = mdev->parent;
> + mutex_lock(&parent->lock);
> +
> + ret = mdev_device_remove_ops(mdev, force_remove);
> + if (ret) {
> + mutex_unlock(&parent->lock);
> + return ret;
> + }
> +
> + mdev_remove_sysfs_files(dev, type);
> + device_unregister(dev);
> + mutex_unlock(&parent->lock);
> + mdev_put_parent(parent);
> + return ret;
> +}
> +
> +static int __init mdev_init(void)
> +{
> + int ret;
> +
> + ret = mdev_bus_register();
> + if (ret) {
> + pr_err("Failed to register mdev bus\n");
> + return ret;
> + }
> +
> + mdev_bus_compat_class = class_compat_register("mdev_bus");
> + if (!mdev_bus_compat_class) {
> + mdev_bus_unregister();
> + return -ENOMEM;
> + }
> +
> + /*
> + * Attempt to load known vfio_mdev. This gives us a working environment
> + * without the user needing to explicitly load vfio_mdev driver.
> + */
> + request_module_nowait("vfio_mdev");
> +
> + return ret;
> +}
> +
> +static void __exit mdev_exit(void)
> +{
> + class_compat_unregister(mdev_bus_compat_class);
> + mdev_bus_unregister();
> +}
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