vfio/mdev: Add mdev/mtype_get_type_group_id()

This returns the index in the supported_type_groups array that is
associated with the mdev_type attached to the struct mdev_device or its
containing struct kobject.

Each mdev_device can be spawned from exactly one mdev_type, which in turn
originates from exactly one supported_type_group.

Drivers are using weird string calculations to try and get back to this
index, providing a direct access to the index removes a bunch of wonky
driver code.

mdev_type->group can be deleted as the group is obtained using the
type_group_id.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Message-Id: <11-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
index 2a20bdaf6142..5ae06f951a09 100644
--- a/drivers/vfio/mdev/mdev_core.c
+++ b/drivers/vfio/mdev/mdev_core.c
@@ -33,6 +33,26 @@ struct device *mdev_parent_dev(struct mdev_device *mdev)
 }
 EXPORT_SYMBOL(mdev_parent_dev);
 
+/*
+ * Return the index in supported_type_groups that this mdev_device was created
+ * from.
+ */
+unsigned int mdev_get_type_group_id(struct mdev_device *mdev)
+{
+	return mdev->type->type_group_id;
+}
+EXPORT_SYMBOL(mdev_get_type_group_id);
+
+/*
+ * 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)
+{
+	return container_of(mtype_kobj, struct mdev_type, kobj)->type_group_id;
+}
+EXPORT_SYMBOL(mtype_get_type_group_id);
+
 /* Should be called holding parent_list_lock */
 static struct mdev_parent *__find_parent_device(struct device *dev)
 {