[PATCH 11/14] rapidio: utilize new device_add_cdev helper function

[Logan Gunthorpe]

Note: the chardev instance in rio_mport_cdev originally did not
set the kobject parent. Thus, I'm reasonably confident that because
of this, this code  would have suffered from a minor use after free
bug if the cdev was open when the backing device was released.

Signed-off-by: Logan Gunthorpe <logang at deltatee.com>
---
 drivers/rapidio/devices/rio_mport_cdev.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/rapidio/devices/rio_mport_cdev.c b/drivers/rapidio/devices/rio_mport_cdev.c
index 9013a58..10a6b54 100644
--- a/drivers/rapidio/devices/rio_mport_cdev.c
+++ b/drivers/rapidio/devices/rio_mport_cdev.c
@@ -2445,23 +2445,26 @@ static struct mport_dev *mport_cdev_add(struct rio_mport *mport)
 	mutex_init(&md->buf_mutex);
 	mutex_init(&md->file_mutex);
 	INIT_LIST_HEAD(&md->file_list);
+
+	device_initialize(&md->dev);
+	md->dev.devt = MKDEV(MAJOR(dev_number), mport->id);
+
 	cdev_init(&md->cdev, &mport_fops);
 	md->cdev.owner = THIS_MODULE;
-	ret = cdev_add(&md->cdev, MKDEV(MAJOR(dev_number), mport->id), 1);
+	ret = device_add_cdev(&md->dev, &md->cdev);
 	if (ret < 0) {
 		kfree(md);
 		rmcd_error("Unable to register a device, err=%d", ret);
 		return NULL;
 	}
 
-	md->dev.devt = md->cdev.dev;
 	md->dev.class = dev_class;
 	md->dev.parent = &mport->dev;
 	md->dev.release = mport_device_release;
 	dev_set_name(&md->dev, DEV_NAME "%d", mport->id);
 	atomic_set(&md->active, 1);
 
-	ret = device_register(&md->dev);
+	ret = device_add(&md->dev);
 	if (ret) {
 		rmcd_error("Failed to register mport %d (err=%d)",
 		       mport->id, ret);
-- 
2.1.4