vfio/mdev: Add missing typesafety around mdev_device

The mdev API should accept and pass a 'struct mdev_device *' in all
places, not pass a 'struct device *' and cast it internally with
to_mdev_device(). Particularly in its struct mdev_driver functions, the
whole point of a bus's struct device_driver wrapper is to provide type
safety compared to the default struct device_driver.

Further, the driver core standard is for bus drivers to expose their
device structure in their public headers that can be used with
container_of() inlines and '&foo->dev' to go between the class levels, and
'&foo->dev' to be used with dev_err/etc driver core helper functions. Move
'struct mdev_device' to mdev.h

Once done this allows moving some one instruction exported functions to
static inlines, which in turns allows removing one of the two grotesque
symbol_get()'s related to mdev in the core code.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Message-Id: <3-v2-d36939638fc6+d54-vfio2_jgg@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 3 insertions, 4 deletions

diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index ae7e322fbe3c..91b7b8b9eb9c 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -124,9 +124,8 @@ static const struct vfio_device_ops vfio_mdev_dev_ops = {
 	.request	= vfio_mdev_request,
 };
 
-static int vfio_mdev_probe(struct device *dev)
+static int vfio_mdev_probe(struct mdev_device *mdev)
 {
-	struct mdev_device *mdev = to_mdev_device(dev);
 	struct vfio_device *vdev;
 	int ret;
 
@@ -144,9 +143,9 @@ static int vfio_mdev_probe(struct device *dev)
 	return 0;
 }
 
-static void vfio_mdev_remove(struct device *dev)
+static void vfio_mdev_remove(struct mdev_device *mdev)
 {
-	struct vfio_device *vdev = dev_get_drvdata(dev);
+	struct vfio_device *vdev = dev_get_drvdata(&mdev->dev);
 
 	vfio_unregister_group_dev(vdev);
 	kfree(vdev);