vfio/mdev: Correct the function signatures for the mdev_type_attributes

The driver core standard is to pass in the properly typed object, the
properly typed attribute and the buffer data. It stems from the root
kobject method:

ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,..)

Each subclass of kobject should provide their own function with the same
signature but more specific types, eg struct device uses:

ssize_t (*show)(struct device *dev, struct device_attribute *attr,..)

In this case the existing signature is:

ssize_t (*show)(struct kobject *kobj, struct device *dev,..)

Where kobj is a 'struct mdev_type *' and dev is 'mdev_type->parent->dev'.

Change the mdev_type related sysfs attribute functions to:

ssize_t (*show)(struct mdev_type *mtype, struct mdev_type_attribute *attr,..)

In order to restore type safety and match the driver core standard

There are no current users of 'attr', but if it is ever needed it would be
hard to add in retroactively, so do it now.

Reviewed-by: Kevin Tian <[e-mail]>
Reviewed-by: Cornelia Huck <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Jason Gunthorpe <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Alex Williamson <[e-mail]>

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

···
 	return &gvt->types[type_group_id];
 }
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	struct intel_vgpu_type *type;
 	unsigned int num = 0;
-	void *gvt = kdev_to_i915(dev)->gvt;
+	void *gvt = kdev_to_i915(mtype_get_parent_dev(mtype))->gvt;
 
-	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(kobj));
+	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(mtype));
 	if (!type)
 		num = 0;
 	else
···
 	return sprintf(buf, "%u\n", num);
 }
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-		char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }
 
-static ssize_t description_show(struct kobject *kobj, struct device *dev,
-		char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	struct intel_vgpu_type *type;
-	void *gvt = kdev_to_i915(dev)->gvt;
+	void *gvt = kdev_to_i915(mtype_get_parent_dev(mtype))->gvt;
 
-	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(kobj));
+	type = intel_gvt_find_vgpu_type(gvt, mtype_get_type_group_id(mtype));
 	if (!type)
 		return 0;
 

drivers/s390/cio/vfio_ccw_ops.c

···
 	return NOTIFY_DONE;
 }
 
-static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "I/O subchannel (Non-QDIO)\n");
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_CCW_STRING);
 }
 static MDEV_TYPE_ATTR_RO(device_api);
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
-	struct vfio_ccw_private *private = dev_get_drvdata(dev);
+	struct vfio_ccw_private *private =
+		dev_get_drvdata(mtype_get_parent_dev(mtype));
 
 	return sprintf(buf, "%d\n", atomic_read(&private->avail));
 }

drivers/s390/crypto/vfio_ap_ops.c

···
 	return 0;
 }
 
-static ssize_t name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_AP_MDEV_NAME_HWVIRT);
 }
 
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t available_instances_show(struct kobject *kobj,
-					struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	return sprintf(buf, "%d\n",
 		       atomic_read(&matrix_dev->available_instances));
···
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_AP_STRING);
 }

drivers/vfio/mdev/mdev_core.c

···
  * Used in mdev_type_attribute sysfs functions to return the index in the
  * supported_type_groups that the sysfs is called from.
  */
-unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj)
+unsigned int mtype_get_type_group_id(struct mdev_type *mtype)
 {
-	return container_of(mtype_kobj, struct mdev_type, kobj)->type_group_id;
+	return mtype->type_group_id;
 }
 EXPORT_SYMBOL(mtype_get_type_group_id);
+
+/*
+ * Used in mdev_type_attribute sysfs functions to return the parent struct
+ * device
+ */
+struct device *mtype_get_parent_dev(struct mdev_type *mtype)
+{
+	return mtype->parent->dev;
+}
+EXPORT_SYMBOL(mtype_get_parent_dev);
 
 /* Should be called holding parent_list_lock */
 static struct mdev_parent *__find_parent_device(struct device *dev)

drivers/vfio/mdev/mdev_sysfs.c

···
 	ssize_t ret = -EIO;
 
 	if (attr->show)
-		ret = attr->show(kobj, type->parent->dev, buf);
+		ret = attr->show(type, attr, buf);
 	return ret;
 }
 
···
 	ssize_t ret = -EIO;
 
 	if (attr->store)
-		ret = attr->store(&type->kobj, type->parent->dev, buf, count);
+		ret = attr->store(type, attr, buf, count);
 	return ret;
 }
 
···
 	.store = mdev_type_attr_store,
 };
 
-static ssize_t create_store(struct kobject *kobj, struct device *dev,
-			    const char *buf, size_t count)
+static ssize_t create_store(struct mdev_type *mtype,
+			    struct mdev_type_attribute *attr, const char *buf,
+			    size_t count)
 {
 	char *str;
 	guid_t uuid;
···
 	if (ret)
 		return ret;
 
-	ret = mdev_device_create(to_mdev_type(kobj), &uuid);
+	ret = mdev_device_create(mtype, &uuid);
 	if (ret)
 		return ret;
 

include/linux/mdev.h

···
 }
 
 unsigned int mdev_get_type_group_id(struct mdev_device *mdev);
-unsigned int mtype_get_type_group_id(struct kobject *mtype_kobj);
+unsigned int mtype_get_type_group_id(struct mdev_type *mtype);
+struct device *mtype_get_parent_dev(struct mdev_type *mtype);
 
 /**
  * struct mdev_parent_ops - Structure to be registered for each parent device to
···
 /* interface for exporting mdev supported type attributes */
 struct mdev_type_attribute {
 	struct attribute attr;
-	ssize_t (*show)(struct kobject *kobj, struct device *dev, char *buf);
-	ssize_t (*store)(struct kobject *kobj, struct device *dev,
-			 const char *buf, size_t count);
+	ssize_t (*show)(struct mdev_type *mtype,
+			struct mdev_type_attribute *attr, char *buf);
+	ssize_t (*store)(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, const char *buf,
+			 size_t count);
 };
 
 #define MDEV_TYPE_ATTR(_name, _mode, _show, _store)		\

samples/vfio-mdev/mbochs.c

···
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n", kobj->name);
+	const struct mbochs_type *type =
+		&mbochs_types[mtype_get_type_group_id(mtype)];
+
+	return sprintf(buf, "%s\n", type->name);
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-description_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(kobj)];
+		&mbochs_types[mtype_get_type_group_id(mtype)];
 
 	return sprintf(buf, "virtual display, %d MB video memory\n",
 		       type ? type->mbytes  : 0);
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	const struct mbochs_type *type =
-		&mbochs_types[mtype_get_type_group_id(kobj)];
+		&mbochs_types[mtype_get_type_group_id(mtype)];
 	int count = (max_mbytes - mbochs_used_mbytes) / type->mbytes;
 
 	return sprintf(buf, "%d\n", count);
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }

samples/vfio-mdev/mdpy.c

···
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%s\n", kobj->name);
+	const struct mdpy_type *type =
+		&mdpy_types[mtype_get_type_group_id(mtype)];
+
+	return sprintf(buf, "%s\n", type->name);
 }
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-description_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t description_show(struct mdev_type *mtype,
+				struct mdev_type_attribute *attr, char *buf)
 {
 	const struct mdpy_type *type =
-		&mdpy_types[mtype_get_type_group_id(kobj)];
+		&mdpy_types[mtype_get_type_group_id(mtype)];
 
 	return sprintf(buf, "virtual display, %dx%d framebuffer\n",
 		       type ? type->width  : 0,
···
 }
 static MDEV_TYPE_ATTR_RO(description);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	return sprintf(buf, "%d\n", max_devices - mdpy_count);
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }

samples/vfio-mdev/mtty.c

···
 	NULL,
 };
 
-static ssize_t
-name_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t name_show(struct mdev_type *mtype,
+			 struct mdev_type_attribute *attr, char *buf)
 {
 	static const char *name_str[2] = { "Single port serial",
 					   "Dual port serial" };
 
 	return sysfs_emit(buf, "%s\n",
-			  name_str[mtype_get_type_group_id(kobj)]);
+			  name_str[mtype_get_type_group_id(mtype)]);
 }
 
 static MDEV_TYPE_ATTR_RO(name);
 
-static ssize_t
-available_instances_show(struct kobject *kobj, struct device *dev, char *buf)
+static ssize_t available_instances_show(struct mdev_type *mtype,
+					struct mdev_type_attribute *attr,
+					char *buf)
 {
 	struct mdev_state *mds;
-	unsigned int ports = mtype_get_type_group_id(kobj) + 1;
+	unsigned int ports = mtype_get_type_group_id(mtype) + 1;
 	int used = 0;
 
 	list_for_each_entry(mds, &mdev_devices_list, next)
···
 
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-
-static ssize_t device_api_show(struct kobject *kobj, struct device *dev,
-			       char *buf)
+static ssize_t device_api_show(struct mdev_type *mtype,
+			       struct mdev_type_attribute *attr, char *buf)
 {
 	return sprintf(buf, "%s\n", VFIO_DEVICE_API_PCI_STRING);
 }