rapidio: make all 'class' structures const

Now that the driver core allows for struct class to be in read-only
memory, making all 'class' structures to be declared at build time
placing them into read-only memory, instead of having to be dynamically
allocated at load time.

Suggested-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Ivan Orlov <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/rapidio/devices/rio_mport_cdev.c

···
 static DECLARE_WAIT_QUEUE_HEAD(mport_cdev_wait);
 #endif
 
-static struct class *dev_class;
+static const struct class dev_class = {
+	.name = DRV_NAME,
+};
 static dev_t dev_number;
 
 static void mport_release_mapping(struct kref *ref);
···
 
 	device_initialize(&md->dev);
 	md->dev.devt = MKDEV(MAJOR(dev_number), mport->id);
-	md->dev.class = dev_class;
+	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);
···
 	int ret;
 
 	/* Create device class needed by udev */
-	dev_class = class_create(DRV_NAME);
-	if (IS_ERR(dev_class)) {
+	ret = class_register(&dev_class);
+	if (ret) {
 		rmcd_error("Unable to create " DRV_NAME " class");
-		return PTR_ERR(dev_class);
+		return ret;
 	}
 
 	ret = alloc_chrdev_region(&dev_number, 0, RIO_MAX_MPORTS, DRV_NAME);
···
 err_cli:
 	unregister_chrdev_region(dev_number, RIO_MAX_MPORTS);
 err_chr:
-	class_destroy(dev_class);
+	class_unregister(&dev_class);
 	return ret;
 }
 
···
 static void __exit mport_exit(void)
 {
 	class_interface_unregister(&rio_mport_interface);
-	class_destroy(dev_class);
+	class_unregister(&dev_class);
 	unregister_chrdev_region(dev_number, RIO_MAX_MPORTS);
 }
 

drivers/rapidio/rio_cm.c

···
 static LIST_HEAD(cm_dev_list);
 static DECLARE_RWSEM(rdev_sem);
 
-static struct class *dev_class;
+static const struct class dev_class = {
+	.name = DRV_NAME,
+};
 static unsigned int dev_major;
 static unsigned int dev_minor_base;
 static dev_t dev_number;
···
 		return ret;
 	}
 
-	riocm_cdev.dev = device_create(dev_class, NULL, devno, NULL, DEV_NAME);
+	riocm_cdev.dev = device_create(&dev_class, NULL, devno, NULL, DEV_NAME);
 	if (IS_ERR(riocm_cdev.dev)) {
 		cdev_del(&riocm_cdev.cdev);
 		return PTR_ERR(riocm_cdev.dev);
···
 	int ret;
 
 	/* Create device class needed by udev */
-	dev_class = class_create(DRV_NAME);
-	if (IS_ERR(dev_class)) {
+	ret = class_register(&dev_class);
+	if (ret) {
 		riocm_error("Cannot create " DRV_NAME " class");
-		return PTR_ERR(dev_class);
+		return ret;
 	}
 
 	ret = alloc_chrdev_region(&dev_number, 0, 1, DRV_NAME);
 	if (ret) {
-		class_destroy(dev_class);
+		class_unregister(&dev_class);
 		return ret;
 	}
 
···
 	class_interface_unregister(&rio_mport_interface);
 err_reg:
 	unregister_chrdev_region(dev_number, 1);
-	class_destroy(dev_class);
+	class_unregister(&dev_class);
 	return ret;
 }
 
···
 	device_unregister(riocm_cdev.dev);
 	cdev_del(&(riocm_cdev.cdev));
 
-	class_destroy(dev_class);
+	class_unregister(&dev_class);
 	unregister_chrdev_region(dev_number, 1);
 }