6 files changed, 23 insertions, 15 deletions

diff --git a/Documentation/vfio-mediated-device.txt b/Documentation/vfio-mediated-device.txt
index cfee106a3679..d226c7a5ba8b 100644
--- a/Documentation/vfio-mediated-device.txt
+++ b/Documentation/vfio-mediated-device.txt
@@ -223,6 +223,9 @@ 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,
diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 081ada238107..38500329aa92 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -396,7 +396,7 @@ static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
         struct device *pdev;
         void *gvt;
 
-        pdev = mdev->parent->dev;
+        pdev = mdev_parent_dev(mdev);
         gvt = kdev_to_i915(pdev)->gvt;
 
         type = intel_gvt_find_vgpu_type(gvt, kobject_name(kobj));
diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index bf3b3b0b3d2b..30d05304241e 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -30,6 +30,12 @@ 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->parent->dev;
+}
+EXPORT_SYMBOL(mdev_parent_dev);
+
 static int _find_mdev_device(struct device *dev, void *data)
 {
         struct mdev_device *mdev;
diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
index 0b72c2d9ee40..b05dd22fc9a6 100644
--- a/drivers/vfio/mdev/mdev_private.h
+++ b/drivers/vfio/mdev/mdev_private.h
@@ -16,6 +16,16 @@
 int  mdev_bus_register(void);
 void mdev_bus_unregister(void);
 
+struct mdev_parent {
+        struct device *dev;
+        const struct mdev_parent_ops *ops;
+        struct kref ref;
+        struct mutex lock;
+        struct list_head next;
+        struct kset *mdev_types_kset;
+        struct list_head type_list;
+};
+
 struct mdev_type {
         struct kobject kobj;
         struct kobject *devices_kobj;
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 853bb78e5866..f586222b6c25 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -13,19 +13,6 @@
 #ifndef MDEV_H
 #define MDEV_H
 
-/* Parent device */
-struct mdev_parent {
-        struct device                   *dev;
-        const struct mdev_parent_ops    *ops;
-
-        /* internal */
-        struct kref             ref;
-        struct mutex            lock;
-        struct list_head        next;
-        struct kset             *mdev_types_kset;
-        struct list_head        type_list;
-};
-
 /* Mediated device */
 struct mdev_device {
         struct device           dev;
@@ -165,4 +152,6 @@ extern void mdev_unregister_device(struct device *dev);
 extern int  mdev_register_driver(struct mdev_driver *drv, struct module *owner);
 extern void mdev_unregister_driver(struct mdev_driver *drv);
 
+extern struct device *mdev_parent_dev(struct mdev_device *mdev);
+
 #endif /* MDEV_H */
diff --git a/samples/vfio-mdev/mtty.c b/samples/vfio-mdev/mtty.c
index 1a74f0e488da..5e13efc62bad 100644
--- a/samples/vfio-mdev/mtty.c
+++ b/samples/vfio-mdev/mtty.c
@@ -734,7 +734,7 @@ int mtty_create(struct kobject *kobj, struct mdev_device *mdev)
 
         for (i = 0; i < 2; i++) {
                 snprintf(name, MTTY_STRING_LEN, "%s-%d",
-                        dev_driver_string(mdev->parent->dev), i + 1);
+                        dev_driver_string(mdev_parent_dev(mdev)), i + 1);
                 if (!strcmp(kobj->name, name)) {
                         nr_ports = i + 1;
                         break;