tee: make tee_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: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/2023100613-lustiness-affiliate-7dcb@gregkhSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tee/tee_core.c

@@ -40,7 +40,10 @@ static const uuid_t tee_client_uuid_ns = UUID_INIT(0x58ac9ca0, 0x2086, 0x4683,
 static DECLARE_BITMAP(dev_mask, TEE_NUM_DEVICES);
 static DEFINE_SPINLOCK(driver_lock);
 
-static struct class *tee_class;
+static const struct class tee_class = {
+	.name = "tee",
+};
+
 static dev_t tee_devt;
 
 struct tee_context *teedev_open(struct tee_device *teedev)
@@ -919,7 +922,7 @@ struct tee_device *tee_device_alloc(const struct tee_desc *teedesc,
 		 teedesc->flags & TEE_DESC_PRIVILEGED ? "priv" : "",
 		 teedev->id - offs);
 
-	teedev->dev.class = tee_class;
+	teedev->dev.class = &tee_class;
 	teedev->dev.release = tee_release_device;
 	teedev->dev.parent = dev;
 
@@ -1112,7 +1115,7 @@ tee_client_open_context(struct tee_context *start,
 		dev = &start->teedev->dev;
 
 	do {
-		dev = class_find_device(tee_class, dev, &match_data, match_dev);
+		dev = class_find_device(&tee_class, dev, &match_data, match_dev);
 		if (!dev) {
 			ctx = ERR_PTR(-ENOENT);
 			break;
@@ -1226,10 +1229,10 @@ static int __init tee_init(void)
 {
 	int rc;
 
-	tee_class = class_create("tee");
-	if (IS_ERR(tee_class)) {
+	rc = class_register(&tee_class);
+	if (rc) {
 		pr_err("couldn't create class\n");
-		return PTR_ERR(tee_class);
+		return rc;
 	}
 
 	rc = alloc_chrdev_region(&tee_devt, 0, TEE_NUM_DEVICES, "tee");
@@ -1249,8 +1252,7 @@ static int __init tee_init(void)
 out_unreg_chrdev:
 	unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES);
 out_unreg_class:
-	class_destroy(tee_class);
-	tee_class = NULL;
+	class_unregister(&tee_class);
 
 	return rc;
 }
@@ -1259,8 +1261,7 @@ static void __exit tee_exit(void)
 {
 	bus_unregister(&tee_bus_type);
 	unregister_chrdev_region(tee_devt, TEE_NUM_DEVICES);
-	class_destroy(tee_class);
-	tee_class = NULL;
+	class_unregister(&tee_class);
 }
 
 subsys_initcall(tee_init);