vfio/mdev: remove mdev_parent_dev

Just open code the dereferences in the only user.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20220923092652.100656-9-hch@lst.deSigned-off-by: Alex Williamson <alex.williamson@redhat.com>

Documentation/driver-api/vfio-mediated-device.rst

@@ -200,9 +200,6 @@ Directories and files under the sysfs for Each Physical Device
 
 	sprintf(buf, "%s-%s", dev_driver_string(parent->dev), group->name);
 
-  (or using mdev_parent_dev(mdev) to arrive at the parent device outside
-  of the core mdev code)
-
 * device_api
 
   This attribute should show which device API is being created, for example,

drivers/gpu/drm/i915/gvt/kvmgt.c

@@ -1488,7 +1488,7 @@ static int intel_vgpu_init_dev(struct vfio_device *vfio_dev)
 	struct intel_vgpu_type *type =
 		container_of(mdev->type, struct intel_vgpu_type, type);
 
-	vgpu->gvt = kdev_to_i915(mdev_parent_dev(mdev))->gvt;
+	vgpu->gvt = kdev_to_i915(mdev->type->parent->dev)->gvt;
 	return intel_gvt_create_vgpu(vgpu, type->conf);
 }
 

drivers/vfio/mdev/mdev_core.c

@@ -23,12 +23,6 @@ static struct class_compat *mdev_bus_compat_class;
 static LIST_HEAD(mdev_list);
 static DEFINE_MUTEX(mdev_list_lock);
 
-struct device *mdev_parent_dev(struct mdev_device *mdev)
-{
-	return mdev->type->parent->dev;
-}
-EXPORT_SYMBOL(mdev_parent_dev);
-
 /*
  * Used in mdev_type_attribute sysfs functions to return the parent struct
  * device

include/linux/mdev.h

@@ -95,7 +95,6 @@ void mdev_unregister_parent(struct mdev_parent *parent);
 int mdev_register_driver(struct mdev_driver *drv);
 void mdev_unregister_driver(struct mdev_driver *drv);
 
-struct device *mdev_parent_dev(struct mdev_device *mdev);
 static inline struct device *mdev_dev(struct mdev_device *mdev)
 {
 	return &mdev->dev;