[PATCH 00/13] Provide core infrastructure for managing open/release

@@ -1274,9 +1274,6 @@ static long mbochs_ioctl(struct vfio_device *vdev, unsigned int cmd,
 
 static int mbochs_open(struct vfio_device *vdev)
 {
-	if (!try_module_get(THIS_MODULE))
-		return -ENODEV;
-
 	return 0;
 }
 

@@ -1300,7 +1297,6 @@ static void mbochs_close(struct vfio_device *vdev)
 	mbochs_put_pages(mdev_state);
 
 	mutex_unlock(&mdev_state->ops_lock);
-	module_put(THIS_MODULE);
 }
 
 static ssize_t

@@ -611,15 +611,11 @@ static long mdpy_ioctl(struct vfio_device *vdev, unsigned int cmd,
 
 static int mdpy_open(struct vfio_device *vdev)
 {
-	if (!try_module_get(THIS_MODULE))
-		return -ENODEV;
-
 	return 0;
 }
 
 static void mdpy_close(struct vfio_device *vdev)
 {
-	module_put(THIS_MODULE);
 }
 
 static ssize_t

@@ -17,6 +17,26 @@
 
 #include "mdev_private.h"
 
+static int vfio_mdev_open_device(struct vfio_device *core_vdev)
+{
+	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
+	struct mdev_parent *parent = mdev->type->parent;
+
+	if (unlikely(!parent->ops->open_device))
+		return -EINVAL;
+
+	return parent->ops->open_device(mdev);
+}
+
+static void vfio_mdev_close_device(struct vfio_device *core_vdev)
+{
+	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
+	struct mdev_parent *parent = mdev->type->parent;
+
+	if (likely(parent->ops->close_device))
+		parent->ops->close_device(mdev);
+}
+
 static int vfio_mdev_open(struct vfio_device *core_vdev)
 {
 	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);

@@ -100,6 +120,8 @@ static void vfio_mdev_request(struct vfio_device *core_vdev, unsigned int count)
 
 static const struct vfio_device_ops vfio_mdev_dev_ops = {
 	.name		= "vfio-mdev",
+	.open_device	= vfio_mdev_open_device,
+	.close_device	= vfio_mdev_close_device,
 	.open		= vfio_mdev_open,
 	.release	= vfio_mdev_release,
 	.ioctl		= vfio_mdev_unlocked_ioctl,

@@ -96,6 +96,74 @@ module_param_named(enable_unsafe_noiommu_mode,
 MODULE_PARM_DESC(enable_unsafe_noiommu_mode, "Enable UNSAFE, no-IOMMU mode.  This mode provides no device isolation, no DMA translation, no host kernel protection, cannot be used for device assignment to virtual machines, requires RAWIO permissions, and will taint the kernel.  If you do not know what this is for, step away. (default: false)");
 #endif
 
+static DEFINE_XARRAY(vfio_device_set_xa);
+
+int vfio_assign_device_set(struct vfio_device *device, void *set_id)
+{
+	struct vfio_device_set *alloc_dev_set = NULL;
+	struct vfio_device_set *dev_set;
+
+	if (WARN_ON(!set_id))
+		return -EINVAL;
+
+	/*
+	 * Atomically acquire a singleton object in the xarray for this set_id
+	 */
+again:
+	xa_lock(&vfio_device_set_xa);
+	if (alloc_dev_set) {
+		dev_set = __xa_cmpxchg(&vfio_device_set_xa,
+				       (unsigned long)set_id, NULL,
+				       alloc_dev_set, GFP_KERNEL);
+		if (xa_is_err(dev_set)) {
+			xa_unlock(&vfio_device_set_xa);
+			kfree(alloc_dev_set);
+			return xa_err(dev_set);
+		}
+		if (!dev_set)
+			dev_set = alloc_dev_set;
+	} else
+		dev_set = xa_load(&vfio_device_set_xa, (unsigned long)set_id);
+	if (dev_set) {
+		dev_set->device_count++;
+		xa_unlock(&vfio_device_set_xa);
+		device->dev_set = dev_set;
+		if (dev_set != alloc_dev_set)
+			kfree(alloc_dev_set);
+		return 0;
+	}
+	xa_unlock(&vfio_device_set_xa);
+
+	if (WARN_ON(alloc_dev_set))
+		return -EINVAL;
+
+	alloc_dev_set = kzalloc(sizeof(*alloc_dev_set), GFP_KERNEL);
+	if (!alloc_dev_set)
+		return -ENOMEM;
+	mutex_init(&alloc_dev_set->lock);
+	alloc_dev_set->set_id = set_id;
+	goto again;
+}
+EXPORT_SYMBOL_GPL(vfio_assign_device_set);
+
+static void vfio_release_device_set(struct vfio_device *device)
+{
+	struct vfio_device_set *dev_set = device->dev_set;
+
+	if (!dev_set)
+		return;
+
+	xa_lock(&vfio_device_set_xa);
+	dev_set->device_count--;
+	if (!dev_set->device_count) {
+		__xa_erase(&vfio_device_set_xa,
+			   (unsigned long)dev_set->set_id);
+		mutex_destroy(&dev_set->lock);
+		kfree(dev_set);
+	}
+	xa_unlock(&vfio_device_set_xa);
+}
+
 /*
  * vfio_iommu_group_{get,put} are only intended for VFIO bus driver probe
  * and remove functions, any use cases other than acquiring the first

@@ -751,6 +819,7 @@ EXPORT_SYMBOL_GPL(vfio_init_group_dev);
 
 void vfio_uninit_group_dev(struct vfio_device *device)
 {
+	vfio_release_device_set(device);
 }
 EXPORT_SYMBOL_GPL(vfio_uninit_group_dev);
 

@@ -760,6 +829,13 @@ int vfio_register_group_dev(struct vfio_device *device)
 	struct iommu_group *iommu_group;
 	struct vfio_group *group;
 
+	/*
+	 * If the driver doesn't specify a set then the device is added to a
+	 * signleton set just for itself.
+	 */
+	if (!device->dev_set)
+		vfio_assign_device_set(device, device);
+
 	iommu_group = iommu_group_get(device->dev);
 	if (!iommu_group)
 		return -EINVAL;

@@ -1361,7 +1437,8 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
 {
 	struct vfio_device *device;
 	struct file *filep;
-	int ret;
+	int fdno;
+	int ret = 0;
 
 	if (0 == atomic_read(&group->container_users) ||
 	    !group->container->iommu_driver || !vfio_group_viable(group))

@@ -1375,38 +1452,38 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
 		return PTR_ERR(device);
 
 	if (!try_module_get(device->dev->driver->owner)) {
-		vfio_device_put(device);
-		return -ENODEV;
+		ret = -ENODEV;
+		goto err_device_put;
 	}
 
-	ret = device->ops->open(device);
-	if (ret) {
-		module_put(device->dev->driver->owner);
-		vfio_device_put(device);
-		return ret;
+	mutex_lock(&device->dev_set->lock);
+	device->open_count++;
+	if (device->open_count == 1 && device->ops->open_device) {
+		ret = device->ops->open_device(device);
+		if (ret)
+			goto err_undo_count;
+	}
+	mutex_unlock(&device->dev_set->lock);
+
+	if (device->ops->open) {
+		ret = device->ops->open(device);
+		if (ret)
+			goto err_close_device;
 	}
 
 	/*
 	 * We can't use anon_inode_getfd() because we need to modify
 	 * the f_mode flags directly to allow more than just ioctls
 	 */
-	ret = get_unused_fd_flags(O_CLOEXEC);
-	if (ret < 0) {
-		device->ops->release(device);
-		module_put(device->dev->driver->owner);
-		vfio_device_put(device);
-		return ret;
-	}
+	fdno = ret = get_unused_fd_flags(O_CLOEXEC);
+	if (ret < 0)
+		goto err_release;
 
 	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
 				   device, O_RDWR);
 	if (IS_ERR(filep)) {
-		put_unused_fd(ret);
 		ret = PTR_ERR(filep);
-		device->ops->release(device);
-		module_put(device->dev->driver->owner);
-		vfio_device_put(device);
-		return ret;
+		goto err_fd;
 	}
 
 	/*

@@ -1418,12 +1495,28 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
 
 	atomic_inc(&group->container_users);
 
-	fd_install(ret, filep);
+	fd_install(fdno, filep);
 
 	if (group->noiommu)
 		dev_warn(device->dev, "vfio-noiommu device opened by user "
 			 "(%s:%d)\n", current->comm, task_pid_nr(current));
+	return fdno;
 
+err_fd:
+	put_unused_fd(fdno);
+err_release:
+	if (device->ops->release)
+		device->ops->release(device);
+err_close_device:
+	mutex_lock(&device->dev_set->lock);
+	if (device->open_count == 1 && device->ops->close_device)
+		device->ops->close_device(device);
+err_undo_count:
+	device->open_count--;
+	mutex_unlock(&device->dev_set->lock);
+	module_put(device->dev->driver->owner);
+err_device_put:
+	vfio_device_put(device);
 	return ret;
 }
 

@@ -1561,7 +1654,13 @@ static int vfio_device_fops_release(struct inode *inode, struct file *filep)
 {
 	struct vfio_device *device = filep->private_data;
 
-	device->ops->release(device);
+	if (device->ops->release)
+		device->ops->release(device);
+
+	mutex_lock(&device->dev_set->lock);
+	if (!--device->open_count && device->ops->close_device)
+		device->ops->close_device(device);
+	mutex_unlock(&device->dev_set->lock);
 
 	module_put(device->dev->driver->owner);
 

@@ -2364,6 +2463,7 @@ static void __exit vfio_cleanup(void)
 	class_destroy(vfio.class);
 	vfio.class = NULL;
 	misc_deregister(&vfio_dev);
+	xa_destroy(&vfio_device_set_xa);
 }
 
 module_init(vfio_init);

@@ -111,6 +111,8 @@ struct mdev_parent_ops {
 
 	int     (*create)(struct mdev_device *mdev);
 	int     (*remove)(struct mdev_device *mdev);
+	int     (*open_device)(struct mdev_device *mdev);
+	void    (*close_device)(struct mdev_device *mdev);
 	int     (*open)(struct mdev_device *mdev);
 	void    (*release)(struct mdev_device *mdev);
 	ssize_t (*read)(struct mdev_device *mdev, char __user *buf,

@@ -15,13 +15,26 @@
 #include <linux/poll.h>
 #include <uapi/linux/vfio.h>
 
+/*
+ * VFIO devices can be placed in a set, this allows all devices to share this
+ * structure and the VFIO core will provide a lock that is held around
+ * open_device()/close_device() for all devices in the set.
+ */
+struct vfio_device_set {
+	void *set_id;
+	struct mutex lock;
+	unsigned int device_count;
+};
+
 struct vfio_device {
 	struct device *dev;
 	const struct vfio_device_ops *ops;
 	struct vfio_group *group;
+	struct vfio_device_set *dev_set;
 
 	/* Members below here are private, not for driver use */
 	refcount_t refcount;
+	unsigned int open_count;
 	struct completion comp;
 	struct list_head group_next;
 };

@@ -29,6 +42,8 @@ struct vfio_device {
 /**
  * struct vfio_device_ops - VFIO bus driver device callbacks
  *
+ * @open_device: Called when the first file descriptor is opened for this device
+ * @close_device: Opposite of open_device
  * @open: Called when userspace creates new file descriptor for device
  * @release: Called when userspace releases file descriptor for device
  * @read: Perform read(2) on device file descriptor

@@ -43,6 +58,8 @@ struct vfio_device {
  */
 struct vfio_device_ops {
 	char	*name;
+	int	(*open_device)(struct vfio_device *vdev);
+	void	(*close_device)(struct vfio_device *vdev);
 	int	(*open)(struct vfio_device *vdev);
 	void	(*release)(struct vfio_device *vdev);
 	ssize_t	(*read)(struct vfio_device *vdev, char __user *buf,

@@ -67,6 +84,8 @@ void vfio_unregister_group_dev(struct vfio_device *device);
 extern struct vfio_device *vfio_device_get_from_dev(struct device *dev);
 extern void vfio_device_put(struct vfio_device *device);
 
+int vfio_assign_device_set(struct vfio_device *device, void *set_id);
+
 /* events for the backend driver notify callback */
 enum vfio_iommu_notify_type {
 	VFIO_IOMMU_CONTAINER_CLOSE = 0,

@@ -255,11 +255,13 @@ vfio_unregister_group_dev() respectively::
 	void vfio_init_group_dev(struct vfio_device *device,
 				struct device *dev,
 				const struct vfio_device_ops *ops);
+	void vfio_uninit_group_dev(struct vfio_device *device);
 	int vfio_register_group_dev(struct vfio_device *device);
 	void vfio_unregister_group_dev(struct vfio_device *device);
 
 The driver should embed the vfio_device in its own structure and call
-vfio_init_group_dev() to pre-configure it before going to registration.
+vfio_init_group_dev() to pre-configure it before going to registration
+and call vfio_uninit_group_dev() after completing the un-registration.
 vfio_register_group_dev() indicates to the core to begin tracking the
 iommu_group of the specified dev and register the dev as owned by a VFIO bus
 driver. Once vfio_register_group_dev() returns it is possible for userspace to

@@ -627,7 +627,7 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
 
 	ret = vfio_fsl_mc_reflck_attach(vdev);
 	if (ret)
-		goto out_kfree;
+		goto out_uninit;
 
 	ret = vfio_fsl_mc_init_device(vdev);
 	if (ret)

@@ -657,7 +657,8 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
 	vfio_fsl_uninit_device(vdev);
 out_reflck:
 	vfio_fsl_mc_reflck_put(vdev->reflck);
-out_kfree:
+out_uninit:
+	vfio_uninit_group_dev(&vdev->vdev);
 	kfree(vdev);
 out_group_put:
 	vfio_iommu_group_put(group, dev);

@@ -674,6 +675,7 @@ static int vfio_fsl_mc_remove(struct fsl_mc_device *mc_dev)
 
 	dprc_remove_devices(mc_dev, NULL, 0);
 	vfio_fsl_uninit_device(vdev);
+	vfio_uninit_group_dev(&vdev->vdev);
 	vfio_fsl_mc_reflck_put(vdev->reflck);
 
 	kfree(vdev);

@@ -120,12 +120,16 @@ static int vfio_mdev_probe(struct mdev_device *mdev)
 
 	vfio_init_group_dev(vdev, &mdev->dev, &vfio_mdev_dev_ops);
 	ret = vfio_register_group_dev(vdev);
-	if (ret) {
-		kfree(vdev);
-		return ret;
-	}
+	if (ret)
+		goto out_uninit;
+
 	dev_set_drvdata(&mdev->dev, vdev);
 	return 0;
+
+out_uninit:
+	vfio_uninit_group_dev(vdev);
+	kfree(vdev);
+	return ret;
 }
 
 static void vfio_mdev_remove(struct mdev_device *mdev)

@@ -133,6 +137,7 @@ static void vfio_mdev_remove(struct mdev_device *mdev)
 	struct vfio_device *vdev = dev_get_drvdata(&mdev->dev);
 
 	vfio_unregister_group_dev(vdev);
+	vfio_uninit_group_dev(vdev);
 	kfree(vdev);
 }
 

@@ -2022,7 +2022,7 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	ret = vfio_pci_reflck_attach(vdev);
 	if (ret)
-		goto out_free;
+		goto out_uninit;
 	ret = vfio_pci_vf_init(vdev);
 	if (ret)
 		goto out_reflck;

@@ -2059,7 +2059,8 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	vfio_pci_vf_uninit(vdev);
 out_reflck:
 	vfio_pci_reflck_put(vdev->reflck);
-out_free:
+out_uninit:
+	vfio_uninit_group_dev(&vdev->vdev);
 	kfree(vdev->pm_save);
 	kfree(vdev);
 out_group_put:

@@ -2077,6 +2078,7 @@ static void vfio_pci_remove(struct pci_dev *pdev)
 
 	vfio_pci_vf_uninit(vdev);
 	vfio_pci_reflck_put(vdev->reflck);
+	vfio_uninit_group_dev(&vdev->vdev);
 	vfio_pci_vga_uninit(vdev);
 
 	vfio_iommu_group_put(pdev->dev.iommu_group, &pdev->dev);

@@ -667,7 +667,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 		ret = vfio_platform_of_probe(vdev, dev);
 
 	if (ret)
-		return ret;
+		goto out_uninit;
 
 	vdev->device = dev;
 

@@ -675,7 +675,7 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 	if (ret && vdev->reset_required) {
 		dev_err(dev, "No reset function found for device %s\n",
 			vdev->name);
-		return ret;
+		goto out_uninit;
 	}
 
 	group = vfio_iommu_group_get(dev);

@@ -698,6 +698,8 @@ int vfio_platform_probe_common(struct vfio_platform_device *vdev,
 	vfio_iommu_group_put(group, dev);
 put_reset:
 	vfio_platform_put_reset(vdev);
+out_uninit:
+	vfio_uninit_group_dev(&vdev->vdev);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(vfio_platform_probe_common);

@@ -708,6 +710,7 @@ void vfio_platform_remove_common(struct vfio_platform_device *vdev)
 
 	pm_runtime_disable(vdev->device);
 	vfio_platform_put_reset(vdev);
+	vfio_uninit_group_dev(&vdev->vdev);
 	vfio_iommu_group_put(vdev->vdev.dev->iommu_group, vdev->vdev.dev);
 }
 EXPORT_SYMBOL_GPL(vfio_platform_remove_common);

@@ -749,6 +749,11 @@ void vfio_init_group_dev(struct vfio_device *device, struct device *dev,
 }
 EXPORT_SYMBOL_GPL(vfio_init_group_dev);
 
+void vfio_uninit_group_dev(struct vfio_device *device)
+{
+}
+EXPORT_SYMBOL_GPL(vfio_uninit_group_dev);
+
 int vfio_register_group_dev(struct vfio_device *device)
 {
 	struct vfio_device *existing_device;

@@ -61,6 +61,7 @@ extern void vfio_iommu_group_put(struct iommu_group *group, struct device *dev);
 
 void vfio_init_group_dev(struct vfio_device *device, struct device *dev,
 			 const struct vfio_device_ops *ops);
+void vfio_uninit_group_dev(struct vfio_device *device);
 int vfio_register_group_dev(struct vfio_device *device);
 void vfio_unregister_group_dev(struct vfio_device *device);
 extern struct vfio_device *vfio_device_get_from_dev(struct device *dev);

@@ -558,6 +558,7 @@ static int mbochs_probe(struct mdev_device *mdev)
 	return 0;
 
 err_mem:
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state->vconfig);
 	kfree(mdev_state);
 	return ret;

@@ -571,6 +572,7 @@ static void mbochs_remove(struct mdev_device *mdev)
 	vfio_unregister_group_dev(&mdev_state->vdev);
 	kfree(mdev_state->pages);
 	kfree(mdev_state->vconfig);
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state);
 }
 

@@ -235,17 +235,16 @@ static int mdpy_probe(struct mdev_device *mdev)
 
 	mdev_state->vconfig = kzalloc(MDPY_CONFIG_SPACE_SIZE, GFP_KERNEL);
 	if (mdev_state->vconfig == NULL) {
-		kfree(mdev_state);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_state;
 	}
 
 	fbsize = roundup_pow_of_two(type->width * type->height * type->bytepp);
 
 	mdev_state->memblk = vmalloc_user(fbsize);
 	if (!mdev_state->memblk) {
-		kfree(mdev_state->vconfig);
-		kfree(mdev_state);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_vconfig;
 	}
 	dev_info(dev, "%s: %s (%dx%d)\n", __func__, type->name, type->width,
 		 type->height);

@@ -260,13 +259,18 @@ static int mdpy_probe(struct mdev_device *mdev)
 	mdpy_count++;
 
 	ret = vfio_register_group_dev(&mdev_state->vdev);
-	if (ret) {
-		kfree(mdev_state->vconfig);
-		kfree(mdev_state);
-		return ret;
-	}
+	if (ret)
+		goto err_mem;
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
+err_mem:
+	vfree(mdev_state->memblk);
+err_vconfig:
+	kfree(mdev_state->vconfig);
+err_state:
+	vfio_uninit_group_dev(&mdev_state->vdev);
+	kfree(mdev_state);
+	return ret;
 }
 
 static void mdpy_remove(struct mdev_device *mdev)

@@ -278,6 +282,7 @@ static void mdpy_remove(struct mdev_device *mdev)
 	vfio_unregister_group_dev(&mdev_state->vdev);
 	vfree(mdev_state->memblk);
 	kfree(mdev_state->vconfig);
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state);
 
 	mdpy_count--;

@@ -718,8 +718,8 @@ static int mtty_probe(struct mdev_device *mdev)
 
 	mdev_state = kzalloc(sizeof(struct mdev_state), GFP_KERNEL);
 	if (mdev_state == NULL) {
-		atomic_add(nr_ports, &mdev_avail_ports);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_nr_ports;
 	}
 
 	vfio_init_group_dev(&mdev_state->vdev, &mdev->dev, &mtty_dev_ops);

@@ -732,9 +732,8 @@ static int mtty_probe(struct mdev_device *mdev)
 	mdev_state->vconfig = kzalloc(MTTY_CONFIG_SPACE_SIZE, GFP_KERNEL);
 
 	if (mdev_state->vconfig == NULL) {
-		kfree(mdev_state);
-		atomic_add(nr_ports, &mdev_avail_ports);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_state;
 	}
 
 	mutex_init(&mdev_state->ops_lock);

@@ -743,14 +742,19 @@ static int mtty_probe(struct mdev_device *mdev)
 	mtty_create_config_space(mdev_state);
 
 	ret = vfio_register_group_dev(&mdev_state->vdev);
-	if (ret) {
-		kfree(mdev_state);
-		atomic_add(nr_ports, &mdev_avail_ports);
-		return ret;
-	}
-
+	if (ret)
+		goto err_vconfig;
 	dev_set_drvdata(&mdev->dev, mdev_state);
 	return 0;
+
+err_vconfig:
+	kfree(mdev_state->vconfig);
+err_state:
+	vfio_uninit_group_dev(&mdev_state->vdev);
+	kfree(mdev_state);
+err_nr_ports:
+	atomic_add(nr_ports, &mdev_avail_ports);
+	return ret;
 }
 
 static void mtty_remove(struct mdev_device *mdev)

@@ -761,6 +765,7 @@ static void mtty_remove(struct mdev_device *mdev)
 	vfio_unregister_group_dev(&mdev_state->vdev);
 
 	kfree(mdev_state->vconfig);
+	vfio_uninit_group_dev(&mdev_state->vdev);
 	kfree(mdev_state);
 	atomic_add(nr_ports, &mdev_avail_ports);
 }

@@ -1274,7 +1274,7 @@ static long mbochs_ioctl(struct vfio_device *vdev, unsigned int cmd,
 	return -ENOTTY;
 }
 
-static void mbochs_close(struct vfio_device *vdev)
+static void mbochs_close_device(struct vfio_device *vdev)
 {
 	struct mdev_state *mdev_state =
 		container_of(vdev, struct mdev_state, vdev);

@@ -1392,7 +1392,7 @@ static struct attribute_group *mdev_type_groups[] = {
 };
 
 static const struct vfio_device_ops mbochs_dev_ops = {
-	.release = mbochs_close,
+	.close_device = mbochs_close_device,
 	.read = mbochs_read,
 	.write = mbochs_write,
 	.ioctl = mbochs_ioctl,

@@ -19,81 +19,10 @@
 
 static struct fsl_mc_driver vfio_fsl_mc_driver;
 
-static DEFINE_MUTEX(reflck_lock);
-
-static void vfio_fsl_mc_reflck_get(struct vfio_fsl_mc_reflck *reflck)
-{
-	kref_get(&reflck->kref);
-}
-
-static void vfio_fsl_mc_reflck_release(struct kref *kref)
-{
-	struct vfio_fsl_mc_reflck *reflck = container_of(kref,
-						      struct vfio_fsl_mc_reflck,
-						      kref);
-
-	mutex_destroy(&reflck->lock);
-	kfree(reflck);
-	mutex_unlock(&reflck_lock);
-}
-
-static void vfio_fsl_mc_reflck_put(struct vfio_fsl_mc_reflck *reflck)
-{
-	kref_put_mutex(&reflck->kref, vfio_fsl_mc_reflck_release, &reflck_lock);
-}
-
-static struct vfio_fsl_mc_reflck *vfio_fsl_mc_reflck_alloc(void)
-{
-	struct vfio_fsl_mc_reflck *reflck;
-
-	reflck = kzalloc(sizeof(*reflck), GFP_KERNEL);
-	if (!reflck)
-		return ERR_PTR(-ENOMEM);
-
-	kref_init(&reflck->kref);
-	mutex_init(&reflck->lock);
-
-	return reflck;
-}
-
-static int vfio_fsl_mc_reflck_attach(struct vfio_fsl_mc_device *vdev)
-{
-	int ret = 0;
-
-	mutex_lock(&reflck_lock);
-	if (is_fsl_mc_bus_dprc(vdev->mc_dev)) {
-		vdev->reflck = vfio_fsl_mc_reflck_alloc();
-		ret = PTR_ERR_OR_ZERO(vdev->reflck);
-	} else {
-		struct device *mc_cont_dev = vdev->mc_dev->dev.parent;
-		struct vfio_device *device;
-		struct vfio_fsl_mc_device *cont_vdev;
-
-		device = vfio_device_get_from_dev(mc_cont_dev);
-		if (!device) {
-			ret = -ENODEV;
-			goto unlock;
-		}
-
-		cont_vdev =
-			container_of(device, struct vfio_fsl_mc_device, vdev);
-		if (!cont_vdev || !cont_vdev->reflck) {
-			vfio_device_put(device);
-			ret = -ENODEV;
-			goto unlock;
-		}
-		vfio_fsl_mc_reflck_get(cont_vdev->reflck);
-		vdev->reflck = cont_vdev->reflck;
-		vfio_device_put(device);
-	}
-
-unlock:
-	mutex_unlock(&reflck_lock);
-	return ret;
-}
-
-static int vfio_fsl_mc_regions_init(struct vfio_fsl_mc_device *vdev)
+static int vfio_fsl_mc_open_device(struct vfio_device *core_vdev)
 {
+	struct vfio_fsl_mc_device *vdev =
+		container_of(core_vdev, struct vfio_fsl_mc_device, vdev);
 	struct fsl_mc_device *mc_dev = vdev->mc_dev;
 	int count = mc_dev->obj_desc.region_count;
 	int i;

@@ -136,58 +65,30 @@ static void vfio_fsl_mc_regions_cleanup(struct vfio_fsl_mc_device *vdev)
 	kfree(vdev->regions);
 }
 
-static int vfio_fsl_mc_open(struct vfio_device *core_vdev)
-{
-	struct vfio_fsl_mc_device *vdev =
-		container_of(core_vdev, struct vfio_fsl_mc_device, vdev);
-	int ret = 0;
-
-	mutex_lock(&vdev->reflck->lock);
-	if (!vdev->refcnt) {
-		ret = vfio_fsl_mc_regions_init(vdev);
-		if (ret)
-			goto out;
-	}
-	vdev->refcnt++;
-out:
-	mutex_unlock(&vdev->reflck->lock);
 
-	return ret;
-}
-
-static void vfio_fsl_mc_release(struct vfio_device *core_vdev)
+static void vfio_fsl_mc_close_device(struct vfio_device *core_vdev)
 {
 	struct vfio_fsl_mc_device *vdev =
 		container_of(core_vdev, struct vfio_fsl_mc_device, vdev);
+	struct fsl_mc_device *mc_dev = vdev->mc_dev;
+	struct device *cont_dev = fsl_mc_cont_dev(&mc_dev->dev);
+	struct fsl_mc_device *mc_cont = to_fsl_mc_device(cont_dev);
 	int ret;
 
-	mutex_lock(&vdev->reflck->lock);
+	vfio_fsl_mc_regions_cleanup(vdev);
 
-	if (!(--vdev->refcnt)) {
-		struct fsl_mc_device *mc_dev = vdev->mc_dev;
-		struct device *cont_dev = fsl_mc_cont_dev(&mc_dev->dev);
-		struct fsl_mc_device *mc_cont = to_fsl_mc_device(cont_dev);
-
-		vfio_fsl_mc_regions_cleanup(vdev);
+	/* reset the device before cleaning up the interrupts */
+	ret = dprc_reset_container(mc_cont->mc_io, 0, mc_cont->mc_handle,
+				   mc_cont->obj_desc.id,
+				   DPRC_RESET_OPTION_NON_RECURSIVE);
 
-		/* reset the device before cleaning up the interrupts */
-		ret = dprc_reset_container(mc_cont->mc_io, 0,
-		      mc_cont->mc_handle,
-			  mc_cont->obj_desc.id,
-			  DPRC_RESET_OPTION_NON_RECURSIVE);
+	if (WARN_ON(ret))
+		dev_warn(&mc_cont->dev,
+			 "VFIO_FLS_MC: reset device has failed (%d)\n", ret);
 
-		if (ret) {
-			dev_warn(&mc_cont->dev, "VFIO_FLS_MC: reset device has failed (%d)\n",
-				 ret);
-			WARN_ON(1);
-		}
+	vfio_fsl_mc_irqs_cleanup(vdev);
 
-		vfio_fsl_mc_irqs_cleanup(vdev);
-
-		fsl_mc_cleanup_irq_pool(mc_cont);
-	}
-
-	mutex_unlock(&vdev->reflck->lock);
+	fsl_mc_cleanup_irq_pool(mc_cont);
 }
 
 static long vfio_fsl_mc_ioctl(struct vfio_device *core_vdev,

@@ -504,8 +405,8 @@ static int vfio_fsl_mc_mmap(struct vfio_device *core_vdev,
 
 static const struct vfio_device_ops vfio_fsl_mc_ops = {
 	.name		= "vfio-fsl-mc",
-	.open		= vfio_fsl_mc_open,
-	.release	= vfio_fsl_mc_release,
+	.open_device	= vfio_fsl_mc_open_device,
+	.close_device	= vfio_fsl_mc_close_device,
 	.ioctl		= vfio_fsl_mc_ioctl,
 	.read		= vfio_fsl_mc_read,
 	.write		= vfio_fsl_mc_write,

@@ -625,13 +526,15 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
 	vdev->mc_dev = mc_dev;
 	mutex_init(&vdev->igate);
 
-	ret = vfio_fsl_mc_reflck_attach(vdev);
+	ret = vfio_assign_device_set(&vdev->vdev, is_fsl_mc_bus_dprc(mc_dev) ?
+							  &mc_dev->dev :
+							  mc_dev->dev.parent);
 	if (ret)
 		goto out_uninit;
 
 	ret = vfio_fsl_mc_init_device(vdev);
 	if (ret)
-		goto out_reflck;
+		goto out_uninit;
 
 	ret = vfio_register_group_dev(&vdev->vdev);
 	if (ret) {

@@ -639,12 +542,6 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
 		goto out_device;
 	}
 
-	/*
-	 * This triggers recursion into vfio_fsl_mc_probe() on another device
-	 * and the vfio_fsl_mc_reflck_attach() must succeed, which relies on the
-	 * vfio_add_group_dev() above. It has no impact on this vdev, so it is
-	 * safe to be after the vfio device is made live.
-	 */
 	ret = vfio_fsl_mc_scan_container(mc_dev);
 	if (ret)
 		goto out_group_dev;

@@ -655,8 +552,6 @@ static int vfio_fsl_mc_probe(struct fsl_mc_device *mc_dev)
 	vfio_unregister_group_dev(&vdev->vdev);
 out_device:
 	vfio_fsl_uninit_device(vdev);
-out_reflck:
-	vfio_fsl_mc_reflck_put(vdev->reflck);
 out_uninit:
 	vfio_uninit_group_dev(&vdev->vdev);
 	kfree(vdev);

@@ -676,7 +571,6 @@ static int vfio_fsl_mc_remove(struct fsl_mc_device *mc_dev)
 	dprc_remove_devices(mc_dev, NULL, 0);
 	vfio_fsl_uninit_device(vdev);
 	vfio_uninit_group_dev(&vdev->vdev);
-	vfio_fsl_mc_reflck_put(vdev->reflck);
 
 	kfree(vdev);
 	vfio_iommu_group_put(mc_dev->dev.iommu_group, dev);

@@ -120,7 +120,7 @@ static int vfio_fsl_mc_set_irq_trigger(struct vfio_fsl_mc_device *vdev,
 	if (start != 0 || count != 1)
 		return -EINVAL;
 
-	mutex_lock(&vdev->reflck->lock);
+	mutex_lock(&vdev->vdev.dev_set->lock);
 	ret = fsl_mc_populate_irq_pool(mc_cont,
 			FSL_MC_IRQ_POOL_MAX_TOTAL_IRQS);
 	if (ret)

@@ -129,7 +129,7 @@ static int vfio_fsl_mc_set_irq_trigger(struct vfio_fsl_mc_device *vdev,
 	ret = vfio_fsl_mc_irqs_allocate(vdev);
 	if (ret)
 		goto unlock;
-	mutex_unlock(&vdev->reflck->lock);
+	mutex_unlock(&vdev->vdev.dev_set->lock);
 
 	if (flags & VFIO_IRQ_SET_DATA_EVENTFD) {
 		s32 fd = *(s32 *)data;

@@ -154,7 +154,7 @@ static int vfio_fsl_mc_set_irq_trigger(struct vfio_fsl_mc_device *vdev,
 	return 0;
 
 unlock:
-	mutex_unlock(&vdev->reflck->lock);
+	mutex_unlock(&vdev->vdev.dev_set->lock);
 	return ret;
 
 }

@@ -22,11 +22,6 @@ struct vfio_fsl_mc_irq {
 	char            *name;
 };
 
-struct vfio_fsl_mc_reflck {
-	struct kref		kref;
-	struct mutex		lock;
-};
-
 struct vfio_fsl_mc_region {
 	u32			flags;
 	u32			type;

@@ -39,9 +34,7 @@ struct vfio_fsl_mc_device {
 	struct vfio_device		vdev;
 	struct fsl_mc_device		*mc_dev;
 	struct notifier_block        nb;
-	int				refcnt;
 	struct vfio_fsl_mc_region	*regions;
-	struct vfio_fsl_mc_reflck   *reflck;
 	struct mutex         igate;
 	struct vfio_fsl_mc_irq      *mc_irqs;
 };

@@ -1274,11 +1274,6 @@ static long mbochs_ioctl(struct vfio_device *vdev, unsigned int cmd,
 	return -ENOTTY;
 }
 
-static int mbochs_open(struct vfio_device *vdev)
-{
-	return 0;
-}
-
 static void mbochs_close(struct vfio_device *vdev)
 {
 	struct mdev_state *mdev_state =

@@ -1397,7 +1392,6 @@ static struct attribute_group *mdev_type_groups[] = {
 };
 
 static const struct vfio_device_ops mbochs_dev_ops = {
-	.open = mbochs_open,
 	.release = mbochs_close,
 	.read = mbochs_read,
 	.write = mbochs_write,

@@ -614,15 +614,6 @@ static long mdpy_ioctl(struct vfio_device *vdev, unsigned int cmd,
 	return -ENOTTY;
 }
 
-static int mdpy_open(struct vfio_device *vdev)
-{
-	return 0;
-}
-
-static void mdpy_close(struct vfio_device *vdev)
-{
-}
-
 static ssize_t
 resolution_show(struct device *dev, struct device_attribute *attr,
 		char *buf)

@@ -717,8 +708,6 @@ static struct attribute_group *mdev_type_groups[] = {
 };
 
 static const struct vfio_device_ops mdpy_dev_ops = {
-	.open = mdpy_open,
-	.release = mdpy_close,
 	.read = mdpy_read,
 	.write = mdpy_write,
 	.ioctl = mdpy_ioctl,

@@ -1207,17 +1207,6 @@ static long mtty_ioctl(struct vfio_device *vdev, unsigned int cmd,
 	return -ENOTTY;
 }
 
-static int mtty_open(struct vfio_device *vdev)
-{
-	pr_info("%s\n", __func__);
-	return 0;
-}
-
-static void mtty_close(struct vfio_device *mdev)
-{
-	pr_info("%s\n", __func__);
-}
-
 static ssize_t
 sample_mtty_dev_show(struct device *dev, struct device_attribute *attr,
 		     char *buf)

@@ -1325,8 +1314,6 @@ static struct attribute_group *mdev_type_groups[] = {
 
 static const struct vfio_device_ops mtty_dev_ops = {
 	.name = "vfio-mtty",
-	.open = mtty_open,
-	.release = mtty_close,
 	.read = mtty_read,
 	.write = mtty_write,
 	.ioctl = mtty_ioctl,

@@ -37,26 +37,6 @@ static void vfio_mdev_close_device(struct vfio_device *core_vdev)
 		parent->ops->close_device(mdev);
 }
 
-static int vfio_mdev_open(struct vfio_device *core_vdev)
-{
-	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->type->parent;
-
-	if (unlikely(!parent->ops->open))
-		return -EINVAL;
-
-	return parent->ops->open(mdev);
-}
-
-static void vfio_mdev_release(struct vfio_device *core_vdev)
-{
-	struct mdev_device *mdev = to_mdev_device(core_vdev->dev);
-	struct mdev_parent *parent = mdev->type->parent;
-
-	if (likely(parent->ops->release))
-		parent->ops->release(mdev);
-}
-
 static long vfio_mdev_unlocked_ioctl(struct vfio_device *core_vdev,
 				     unsigned int cmd, unsigned long arg)
 {

@@ -122,8 +102,6 @@ static const struct vfio_device_ops vfio_mdev_dev_ops = {
 	.name		= "vfio-mdev",
 	.open_device	= vfio_mdev_open_device,
 	.close_device	= vfio_mdev_close_device,
-	.open		= vfio_mdev_open,
-	.release	= vfio_mdev_release,
 	.ioctl		= vfio_mdev_unlocked_ioctl,
 	.read		= vfio_mdev_read,
 	.write		= vfio_mdev_write,

@@ -1475,19 +1475,13 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
 	}
 	mutex_unlock(&device->dev_set->lock);
 
-	if (device->ops->open) {
-		ret = device->ops->open(device);
-		if (ret)
-			goto err_close_device;
-	}
-
 	/*
 	 * We can't use anon_inode_getfd() because we need to modify
 	 * the f_mode flags directly to allow more than just ioctls
 	 */
 	fdno = ret = get_unused_fd_flags(O_CLOEXEC);
 	if (ret < 0)
-		goto err_release;
+		goto err_close_device;
 
 	filep = anon_inode_getfile("[vfio-device]", &vfio_device_fops,
 				   device, O_RDWR);