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 <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <18-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index c3a800051d61..1fb34ea394ad 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -47,7 +47,8 @@ static inline struct device *mdev_get_iommu_device(struct mdev_device *mdev)
 }
 
 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
@@ -123,9 +124,11 @@ struct mdev_parent_ops {
 /* 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)		\