2016-11-17 04:46:13 +08:00
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/*
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* Mediated device Core Driver
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*
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* Copyright (c) 2016, NVIDIA CORPORATION. All rights reserved.
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* Author: Neo Jia <cjia@nvidia.com>
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* Kirti Wankhede <kwankhede@nvidia.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/uuid.h>
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#include <linux/sysfs.h>
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#include <linux/mdev.h>
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#include "mdev_private.h"
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#define DRIVER_VERSION "0.1"
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#define DRIVER_AUTHOR "NVIDIA Corporation"
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#define DRIVER_DESC "Mediated device Core Driver"
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static LIST_HEAD(parent_list);
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static DEFINE_MUTEX(parent_list_lock);
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static struct class_compat *mdev_bus_compat_class;
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static int _find_mdev_device(struct device *dev, void *data)
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{
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struct mdev_device *mdev;
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if (!dev_is_mdev(dev))
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return 0;
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mdev = to_mdev_device(dev);
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if (uuid_le_cmp(mdev->uuid, *(uuid_le *)data) == 0)
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return 1;
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return 0;
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}
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static bool mdev_device_exist(struct parent_device *parent, uuid_le uuid)
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{
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struct device *dev;
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dev = device_find_child(parent->dev, &uuid, _find_mdev_device);
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if (dev) {
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put_device(dev);
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return true;
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}
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return false;
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}
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/* Should be called holding parent_list_lock */
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static struct parent_device *__find_parent_device(struct device *dev)
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{
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struct parent_device *parent;
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list_for_each_entry(parent, &parent_list, next) {
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if (parent->dev == dev)
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return parent;
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}
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return NULL;
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}
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static void mdev_release_parent(struct kref *kref)
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{
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struct parent_device *parent = container_of(kref, struct parent_device,
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ref);
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struct device *dev = parent->dev;
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kfree(parent);
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put_device(dev);
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}
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static
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inline struct parent_device *mdev_get_parent(struct parent_device *parent)
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{
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if (parent)
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kref_get(&parent->ref);
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return parent;
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}
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static inline void mdev_put_parent(struct parent_device *parent)
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{
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if (parent)
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kref_put(&parent->ref, mdev_release_parent);
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}
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static int mdev_device_create_ops(struct kobject *kobj,
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struct mdev_device *mdev)
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{
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struct parent_device *parent = mdev->parent;
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int ret;
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ret = parent->ops->create(kobj, mdev);
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if (ret)
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return ret;
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ret = sysfs_create_groups(&mdev->dev.kobj,
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parent->ops->mdev_attr_groups);
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if (ret)
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parent->ops->remove(mdev);
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return ret;
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}
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/*
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* mdev_device_remove_ops gets called from sysfs's 'remove' and when parent
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* device is being unregistered from mdev device framework.
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* - 'force_remove' is set to 'false' when called from sysfs's 'remove' which
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* indicates that if the mdev device is active, used by VMM or userspace
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* application, vendor driver could return error then don't remove the device.
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* - 'force_remove' is set to 'true' when called from mdev_unregister_device()
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* which indicate that parent device is being removed from mdev device
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* framework so remove mdev device forcefully.
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*/
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static int mdev_device_remove_ops(struct mdev_device *mdev, bool force_remove)
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{
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struct parent_device *parent = mdev->parent;
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int ret;
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/*
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* Vendor driver can return error if VMM or userspace application is
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* using this mdev device.
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*/
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ret = parent->ops->remove(mdev);
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if (ret && !force_remove)
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return -EBUSY;
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sysfs_remove_groups(&mdev->dev.kobj, parent->ops->mdev_attr_groups);
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return 0;
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}
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static int mdev_device_remove_cb(struct device *dev, void *data)
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{
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if (!dev_is_mdev(dev))
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return 0;
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return mdev_device_remove(dev, data ? *(bool *)data : true);
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}
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/*
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* mdev_register_device : Register a device
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* @dev: device structure representing parent device.
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* @ops: Parent device operation structure to be registered.
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*
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* Add device to list of registered parent devices.
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* Returns a negative value on error, otherwise 0.
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*/
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int mdev_register_device(struct device *dev, const struct parent_ops *ops)
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{
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int ret;
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struct parent_device *parent;
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/* check for mandatory ops */
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if (!ops || !ops->create || !ops->remove || !ops->supported_type_groups)
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return -EINVAL;
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dev = get_device(dev);
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if (!dev)
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return -EINVAL;
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mutex_lock(&parent_list_lock);
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/* Check for duplicate */
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parent = __find_parent_device(dev);
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if (parent) {
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ret = -EEXIST;
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goto add_dev_err;
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}
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parent = kzalloc(sizeof(*parent), GFP_KERNEL);
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if (!parent) {
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ret = -ENOMEM;
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goto add_dev_err;
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}
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kref_init(&parent->ref);
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mutex_init(&parent->lock);
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parent->dev = dev;
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parent->ops = ops;
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if (!mdev_bus_compat_class) {
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mdev_bus_compat_class = class_compat_register("mdev_bus");
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if (!mdev_bus_compat_class) {
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ret = -ENOMEM;
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goto add_dev_err;
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}
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}
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ret = parent_create_sysfs_files(parent);
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if (ret)
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goto add_dev_err;
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ret = class_compat_create_link(mdev_bus_compat_class, dev, NULL);
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if (ret)
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dev_warn(dev, "Failed to create compatibility class link\n");
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list_add(&parent->next, &parent_list);
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mutex_unlock(&parent_list_lock);
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dev_info(dev, "MDEV: Registered\n");
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return 0;
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add_dev_err:
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mutex_unlock(&parent_list_lock);
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if (parent)
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mdev_put_parent(parent);
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else
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put_device(dev);
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return ret;
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}
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EXPORT_SYMBOL(mdev_register_device);
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/*
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* mdev_unregister_device : Unregister a parent device
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* @dev: device structure representing parent device.
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*
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* Remove device from list of registered parent devices. Give a chance to free
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* existing mediated devices for given device.
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*/
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void mdev_unregister_device(struct device *dev)
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{
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struct parent_device *parent;
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bool force_remove = true;
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mutex_lock(&parent_list_lock);
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parent = __find_parent_device(dev);
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if (!parent) {
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mutex_unlock(&parent_list_lock);
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return;
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}
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dev_info(dev, "MDEV: Unregistering\n");
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list_del(&parent->next);
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class_compat_remove_link(mdev_bus_compat_class, dev, NULL);
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device_for_each_child(dev, (void *)&force_remove,
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mdev_device_remove_cb);
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parent_remove_sysfs_files(parent);
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mutex_unlock(&parent_list_lock);
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mdev_put_parent(parent);
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}
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EXPORT_SYMBOL(mdev_unregister_device);
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static void mdev_device_release(struct device *dev)
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{
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struct mdev_device *mdev = to_mdev_device(dev);
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dev_dbg(&mdev->dev, "MDEV: destroying\n");
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kfree(mdev);
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}
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int mdev_device_create(struct kobject *kobj, struct device *dev, uuid_le uuid)
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{
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int ret;
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struct mdev_device *mdev;
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struct parent_device *parent;
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struct mdev_type *type = to_mdev_type(kobj);
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parent = mdev_get_parent(type->parent);
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if (!parent)
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return -EINVAL;
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mutex_lock(&parent->lock);
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/* Check for duplicate */
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if (mdev_device_exist(parent, uuid)) {
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ret = -EEXIST;
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goto create_err;
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}
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mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
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if (!mdev) {
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ret = -ENOMEM;
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goto create_err;
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}
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memcpy(&mdev->uuid, &uuid, sizeof(uuid_le));
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mdev->parent = parent;
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kref_init(&mdev->ref);
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mdev->dev.parent = dev;
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mdev->dev.bus = &mdev_bus_type;
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mdev->dev.release = mdev_device_release;
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dev_set_name(&mdev->dev, "%pUl", uuid.b);
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ret = device_register(&mdev->dev);
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if (ret) {
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put_device(&mdev->dev);
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goto create_err;
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}
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ret = mdev_device_create_ops(kobj, mdev);
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if (ret)
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goto create_failed;
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ret = mdev_create_sysfs_files(&mdev->dev, type);
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if (ret) {
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mdev_device_remove_ops(mdev, true);
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goto create_failed;
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}
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mdev->type_kobj = kobj;
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dev_dbg(&mdev->dev, "MDEV: created\n");
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mutex_unlock(&parent->lock);
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return ret;
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create_failed:
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device_unregister(&mdev->dev);
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create_err:
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mutex_unlock(&parent->lock);
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mdev_put_parent(parent);
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return ret;
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}
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int mdev_device_remove(struct device *dev, bool force_remove)
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{
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struct mdev_device *mdev;
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struct parent_device *parent;
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struct mdev_type *type;
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int ret;
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mdev = to_mdev_device(dev);
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type = to_mdev_type(mdev->type_kobj);
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parent = mdev->parent;
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mutex_lock(&parent->lock);
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ret = mdev_device_remove_ops(mdev, force_remove);
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if (ret) {
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mutex_unlock(&parent->lock);
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return ret;
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}
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mdev_remove_sysfs_files(dev, type);
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device_unregister(dev);
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mutex_unlock(&parent->lock);
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mdev_put_parent(parent);
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return ret;
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}
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static int __init mdev_init(void)
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{
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2016-11-17 04:46:14 +08:00
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int ret;
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ret = mdev_bus_register();
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/*
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* Attempt to load known vfio_mdev. This gives us a working environment
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* without the user needing to explicitly load vfio_mdev driver.
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*/
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if (!ret)
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request_module_nowait("vfio_mdev");
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return ret;
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2016-11-17 04:46:13 +08:00
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}
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static void __exit mdev_exit(void)
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{
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if (mdev_bus_compat_class)
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class_compat_unregister(mdev_bus_compat_class);
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mdev_bus_unregister();
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}
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module_init(mdev_init)
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module_exit(mdev_exit)
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MODULE_VERSION(DRIVER_VERSION);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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