1 files changed, 41 insertions, 51 deletions

diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 4a806a2273b5..6ae4d012d800 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -11,7 +11,6 @@
  */
 
 #include <linux/vfio.h>
-#include <linux/mdev.h>
 #include <linux/nospec.h>
 #include <linux/slab.h>
 
@@ -45,47 +44,14 @@ static void vfio_ccw_dma_unmap(struct vfio_device *vdev, u64 iova, u64 length)
 	vfio_ccw_mdev_reset(private);
 }
 
-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 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 mdev_type *mtype,
-					struct mdev_type_attribute *attr,
-					char *buf)
+static int vfio_ccw_mdev_init_dev(struct vfio_device *vdev)
 {
 	struct vfio_ccw_private *private =
-		dev_get_drvdata(mtype_get_parent_dev(mtype));
+		container_of(vdev, struct vfio_ccw_private, vdev);
 
-	return sprintf(buf, "%d\n", atomic_read(&private->avail));
+	init_completion(&private->release_comp);
+	return 0;
 }
-static MDEV_TYPE_ATTR_RO(available_instances);
-
-static struct attribute *mdev_types_attrs[] = {
-	&mdev_type_attr_name.attr,
-	&mdev_type_attr_device_api.attr,
-	&mdev_type_attr_available_instances.attr,
-	NULL,
-};
-
-static struct attribute_group mdev_type_group = {
-	.name  = "io",
-	.attrs = mdev_types_attrs,
-};
-
-static struct attribute_group *mdev_type_groups[] = {
-	&mdev_type_group,
-	NULL,
-};
 
 static int vfio_ccw_mdev_probe(struct mdev_device *mdev)
 {
@@ -95,12 +61,9 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev)
 	if (private->state == VFIO_CCW_STATE_NOT_OPER)
 		return -ENODEV;
 
-	if (atomic_dec_if_positive(&private->avail) < 0)
-		return -EPERM;
-
-	memset(&private->vdev, 0, sizeof(private->vdev));
-	vfio_init_group_dev(&private->vdev, &mdev->dev,
-			    &vfio_ccw_dev_ops);
+	ret = vfio_init_device(&private->vdev, &mdev->dev, &vfio_ccw_dev_ops);
+	if (ret)
+		return ret;
 
 	VFIO_CCW_MSG_EVENT(2, "sch %x.%x.%04x: create\n",
 			   private->sch->schid.cssid,
@@ -109,16 +72,32 @@ static int vfio_ccw_mdev_probe(struct mdev_device *mdev)
 
 	ret = vfio_register_emulated_iommu_dev(&private->vdev);
 	if (ret)
-		goto err_atomic;
+		goto err_put_vdev;
 	dev_set_drvdata(&mdev->dev, private);
 	return 0;
 
-err_atomic:
-	vfio_uninit_group_dev(&private->vdev);
-	atomic_inc(&private->avail);
+err_put_vdev:
+	vfio_put_device(&private->vdev);
 	return ret;
 }
 
+static void vfio_ccw_mdev_release_dev(struct vfio_device *vdev)
+{
+	struct vfio_ccw_private *private =
+		container_of(vdev, struct vfio_ccw_private, vdev);
+
+	/*
+	 * We cannot free vfio_ccw_private here because it includes
+	 * parent info which must be free'ed by css driver.
+	 *
+	 * Use a workaround by memset'ing the core device part and
+	 * then notifying the remove path that all active references
+	 * to this device have been released.
+	 */
+	memset(vdev, 0, sizeof(*vdev));
+	complete(&private->release_comp);
+}
+
 static void vfio_ccw_mdev_remove(struct mdev_device *mdev)
 {
 	struct vfio_ccw_private *private = dev_get_drvdata(mdev->dev.parent);
@@ -130,8 +109,16 @@ static void vfio_ccw_mdev_remove(struct mdev_device *mdev)
 
 	vfio_unregister_group_dev(&private->vdev);
 
-	vfio_uninit_group_dev(&private->vdev);
-	atomic_inc(&private->avail);
+	vfio_put_device(&private->vdev);
+	/*
+	 * Wait for all active references on mdev are released so it
+	 * is safe to defer kfree() to a later point.
+	 *
+	 * TODO: the clean fix is to split parent/mdev info from ccw
+	 * private structure so each can be managed in its own life
+	 * cycle.
+	 */
+	wait_for_completion(&private->release_comp);
 }
 
 static int vfio_ccw_mdev_open_device(struct vfio_device *vdev)
@@ -592,6 +579,8 @@ static void vfio_ccw_mdev_request(struct vfio_device *vdev, unsigned int count)
 }
 
 static const struct vfio_device_ops vfio_ccw_dev_ops = {
+	.init = vfio_ccw_mdev_init_dev,
+	.release = vfio_ccw_mdev_release_dev,
 	.open_device = vfio_ccw_mdev_open_device,
 	.close_device = vfio_ccw_mdev_close_device,
 	.read = vfio_ccw_mdev_read,
@@ -602,6 +591,8 @@ static const struct vfio_device_ops vfio_ccw_dev_ops = {
 };
 
 struct mdev_driver vfio_ccw_mdev_driver = {
+	.device_api = VFIO_DEVICE_API_CCW_STRING,
+	.max_instances = 1,
 	.driver = {
 		.name = "vfio_ccw_mdev",
 		.owner = THIS_MODULE,
@@ -609,5 +600,4 @@ struct mdev_driver vfio_ccw_mdev_driver = {
 	},
 	.probe = vfio_ccw_mdev_probe,
 	.remove = vfio_ccw_mdev_remove,
-	.supported_type_groups  = mdev_type_groups,
 };