uacce: make uacce_class constant

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

Cc: Zhou Wang <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: [e-mail]
Tested-by: Zhangfei Gao <[e-mail]>
Link: https://lore.kernel.org/r/2023102458-designate-vicinity-4c86@gregkh
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/uacce/uacce.c

···
 #include <linux/slab.h>
 #include <linux/uacce.h>
 
-static struct class *uacce_class;
 static dev_t uacce_devt;
 static DEFINE_XARRAY_ALLOC(uacce_xa);
+
+static const struct class uacce_class = {
+	.name = UACCE_NAME,
+};
 
 /*
  * If the parent driver or the device disappears, the queue state is invalid and
···
 	mutex_init(&uacce->mutex);
 	device_initialize(&uacce->dev);
 	uacce->dev.devt = MKDEV(MAJOR(uacce_devt), uacce->dev_id);
-	uacce->dev.class = uacce_class;
+	uacce->dev.class = &uacce_class;
 	uacce->dev.groups = uacce_dev_groups;
 	uacce->dev.parent = uacce->parent;
 	uacce->dev.release = uacce_release;
···
 {
 	int ret;
 
-	uacce_class = class_create(UACCE_NAME);
-	if (IS_ERR(uacce_class))
-		return PTR_ERR(uacce_class);
+	ret = class_register(&uacce_class);
+	if (ret)
+		return ret;
 
 	ret = alloc_chrdev_region(&uacce_devt, 0, MINORMASK, UACCE_NAME);
 	if (ret)
-		class_destroy(uacce_class);
+		class_unregister(&uacce_class);
 
 	return ret;
 }
···
 static __exit void uacce_exit(void)
 {
 	unregister_chrdev_region(uacce_devt, MINORMASK);
-	class_destroy(uacce_class);
+	class_unregister(&uacce_class);
 }
 
 subsys_initcall(uacce_init);