scsi: iscsi: Fix possible memory leak when device_register() failed

If device_register() returns error, the name allocated by the
dev_set_name() need be freed. As described in the comment of
device_register(), we should use put_device() to give up the reference in
the error path.

Fix this by calling put_device(), the name will be freed in the
kobject_cleanup(), and this patch modified resources will be released by
calling the corresponding callback function in the device_release().

Signed-off-by: Zhou Guanghui <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Mike Christie <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/scsi_transport_iscsi.c

···
 	dev_set_name(&ep->dev, "ep-%d", id);
 	err = device_register(&ep->dev);
         if (err)
-		goto free_id;
+		goto put_dev;
 
 	err = sysfs_create_group(&ep->dev.kobj, &iscsi_endpoint_group);
 	if (err)
···
 	device_unregister(&ep->dev);
 	return NULL;
 
-free_id:
+put_dev:
 	mutex_lock(&iscsi_ep_idr_mutex);
 	idr_remove(&iscsi_ep_idr, id);
 	mutex_unlock(&iscsi_ep_idr_mutex);
+	put_device(&ep->dev);
+	return NULL;
 free_ep:
 	kfree(ep);
 	return NULL;
···
 
 	err = device_register(&iface->dev);
 	if (err)
-		goto free_iface;
+		goto put_dev;
 
 	err = sysfs_create_group(&iface->dev.kobj, &iscsi_iface_group);
 	if (err)
···
 	device_unregister(&iface->dev);
 	return NULL;
 
-free_iface:
-	put_device(iface->dev.parent);
-	kfree(iface);
+put_dev:
+	put_device(&iface->dev);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(iscsi_create_iface);
···
 
 	err = device_register(&fnode_sess->dev);
 	if (err)
-		goto free_fnode_sess;
+		goto put_dev;
 
 	if (dd_size)
 		fnode_sess->dd_data = &fnode_sess[1];
 
 	return fnode_sess;
 
-free_fnode_sess:
-	kfree(fnode_sess);
+put_dev:
+	put_device(&fnode_sess->dev);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(iscsi_create_flashnode_sess);
···
 
 	err = device_register(&fnode_conn->dev);
 	if (err)
-		goto free_fnode_conn;
+		goto put_dev;
 
 	if (dd_size)
 		fnode_conn->dd_data = &fnode_conn[1];
 
 	return fnode_conn;
 
-free_fnode_conn:
-	kfree(fnode_conn);
+put_dev:
+	put_device(&fnode_conn->dev);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(iscsi_create_flashnode_conn);
···
 	dev_set_name(&priv->dev, "%s", tt->name);
 	err = device_register(&priv->dev);
 	if (err)
-		goto free_priv;
+		goto put_dev;
 
 	err = sysfs_create_group(&priv->dev.kobj, &iscsi_transport_group);
 	if (err)
···
 unregister_dev:
 	device_unregister(&priv->dev);
 	return NULL;
-free_priv:
-	kfree(priv);
+put_dev:
+	put_device(&priv->dev);
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(iscsi_register_transport);