vfio/mdev: simplify mdev_type handling

Instead of abusing struct attribute_group to control initialization of
struct mdev_type, just define the actual attributes in the mdev_driver,
allocate the mdev_type structures in the caller and pass them to
mdev_register_parent.

This allows the caller to use container_of to get at the containing
structure and thus significantly simplify the code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Tony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Eric Farman <farman@linux.ibm.com>
Link: https://lore.kernel.org/r/20220923092652.100656-6-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

5 files changed, 16 insertions, 27 deletions

diff --git a/drivers/s390/cio/vfio_ccw_drv.c b/drivers/s390/cio/vfio_ccw_drv.c
index 7d105915bd14..25a5de08b390 100644
--- a/drivers/s390/cio/vfio_ccw_drv.c
+++ b/drivers/s390/cio/vfio_ccw_drv.c
@@ -202,7 +202,6 @@ static void vfio_ccw_free_private(struct vfio_ccw_private *private)
 	mutex_destroy(&private->io_mutex);
 	kfree(private);
 }
-
 static int vfio_ccw_sch_probe(struct subchannel *sch)
 {
 	struct pmcw *pmcw = &sch->schib.pmcw;
@@ -221,8 +220,11 @@ static int vfio_ccw_sch_probe(struct subchannel *sch)
 
 	dev_set_drvdata(&sch->dev, private);
 
+	private->mdev_type.sysfs_name = "io";
+	private->mdev_types[0] = &private->mdev_type;
 	ret = mdev_register_parent(&private->parent, &sch->dev,
-				   &vfio_ccw_mdev_driver);
+				   &vfio_ccw_mdev_driver,
+				   private->mdev_types, 1);
 	if (ret)
 		goto out_free;
 
diff --git a/drivers/s390/cio/vfio_ccw_ops.c b/drivers/s390/cio/vfio_ccw_ops.c
index 9a0e0c5ffb1a..c37e712a4b06 100644
--- a/drivers/s390/cio/vfio_ccw_ops.c
+++ b/drivers/s390/cio/vfio_ccw_ops.c
@@ -69,23 +69,13 @@ static ssize_t available_instances_show(struct mdev_type *mtype,
 }
 static MDEV_TYPE_ATTR_RO(available_instances);
 
-static struct attribute *mdev_types_attrs[] = {
+static const 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_init_dev(struct vfio_device *vdev)
 {
 	struct vfio_ccw_private *private =
@@ -646,5 +636,5 @@ struct mdev_driver vfio_ccw_mdev_driver = {
 	},
 	.probe = vfio_ccw_mdev_probe,
 	.remove = vfio_ccw_mdev_remove,
-	.supported_type_groups  = mdev_type_groups,
+	.types_attrs = mdev_types_attrs,
 };
diff --git a/drivers/s390/cio/vfio_ccw_private.h b/drivers/s390/cio/vfio_ccw_private.h
index 1a4bfb1b5a80..52caa721ec06 100644
--- a/drivers/s390/cio/vfio_ccw_private.h
+++ b/drivers/s390/cio/vfio_ccw_private.h
@@ -120,6 +120,8 @@ struct vfio_ccw_private {
 	struct completion	release_comp;
 
 	struct mdev_parent	parent;
+	struct mdev_type	mdev_type;
+	struct mdev_type	*mdev_types[1];
 } __aligned(8);
 
 int vfio_ccw_sch_quiesce(struct subchannel *sch);
diff --git a/drivers/s390/crypto/vfio_ap_ops.c b/drivers/s390/crypto/vfio_ap_ops.c
index 724d09a74a8f..24d131c502ca 100644
--- a/drivers/s390/crypto/vfio_ap_ops.c
+++ b/drivers/s390/crypto/vfio_ap_ops.c
@@ -816,23 +816,13 @@ static ssize_t device_api_show(struct mdev_type *mtype,
 
 static MDEV_TYPE_ATTR_RO(device_api);
 
-static struct attribute *vfio_ap_mdev_type_attrs[] = {
+static const struct attribute *vfio_ap_mdev_type_attrs[] = {
 	&mdev_type_attr_name.attr,
 	&mdev_type_attr_device_api.attr,
 	&mdev_type_attr_available_instances.attr,
 	NULL,
 };
 
-static struct attribute_group vfio_ap_mdev_hwvirt_type_group = {
-	.name = VFIO_AP_MDEV_TYPE_HWVIRT,
-	.attrs = vfio_ap_mdev_type_attrs,
-};
-
-static struct attribute_group *vfio_ap_mdev_type_groups[] = {
-	&vfio_ap_mdev_hwvirt_type_group,
-	NULL,
-};
-
 #define MDEV_SHARING_ERR "Userspace may not re-assign queue %02lx.%04lx " \
 			 "already assigned to %s"
 
@@ -1817,7 +1807,7 @@ static struct mdev_driver vfio_ap_matrix_driver = {
 	},
 	.probe = vfio_ap_mdev_probe,
 	.remove = vfio_ap_mdev_remove,
-	.supported_type_groups = vfio_ap_mdev_type_groups,
+	.types_attrs = vfio_ap_mdev_type_attrs,
 };
 
 int vfio_ap_mdev_register(void)
@@ -1830,8 +1820,11 @@ int vfio_ap_mdev_register(void)
 	if (ret)
 		return ret;
 
+	matrix_dev->mdev_type.sysfs_name = VFIO_AP_MDEV_TYPE_HWVIRT;
+	matrix_dev->mdev_types[0] = &matrix_dev->mdev_type;
 	ret = mdev_register_parent(&matrix_dev->parent, &matrix_dev->device,
-				   &vfio_ap_matrix_driver);
+				   &vfio_ap_matrix_driver,
+				   matrix_dev->mdev_types, 1);
 	if (ret)
 		goto err_driver;
 	return 0;
diff --git a/drivers/s390/crypto/vfio_ap_private.h b/drivers/s390/crypto/vfio_ap_private.h
index 35165730f517..441dc8dda380 100644
--- a/drivers/s390/crypto/vfio_ap_private.h
+++ b/drivers/s390/crypto/vfio_ap_private.h
@@ -53,6 +53,8 @@ struct ap_matrix_dev {
 	struct ap_driver  *vfio_ap_drv;
 	struct mutex guests_lock; /* serializes access to each KVM guest */
 	struct mdev_parent parent;
+	struct mdev_type mdev_type;
+	struct mdev_type *mdev_types[];
 };
 
 extern struct ap_matrix_dev *matrix_dev;