cxl: make cxl_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: Andrew Donnellan <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Cc: [e-mail]
Acked-by: Frederic Barrat <[e-mail]>
Link: https://lore.kernel.org/r/2023102434-haiku-uphill-0c11@gregkh
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/cxl/file.c

···
 
 static dev_t cxl_dev;
 
-static struct class *cxl_class;
-
 static int __afu_open(struct inode *inode, struct file *file, bool master)
 {
 	struct cxl *adapter;
···
 	return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev));
 }
 
-extern struct class *cxl_class;
+static const struct class cxl_class = {
+	.name =		"cxl",
+	.devnode =	cxl_devnode,
+};
 
 static int cxl_add_chardev(struct cxl_afu *afu, dev_t devt, struct cdev *cdev,
 			   struct device **chardev, char *postfix, char *desc,
···
 		return rc;
 	}
 
-	dev = device_create(cxl_class, &afu->dev, devt, afu,
+	dev = device_create(&cxl_class, &afu->dev, devt, afu,
 			"afu%i.%i%s", afu->adapter->adapter_num, afu->slice, postfix);
 	if (IS_ERR(dev)) {
 		rc = PTR_ERR(dev);
···
 
 int cxl_register_afu(struct cxl_afu *afu)
 {
-	afu->dev.class = cxl_class;
+	afu->dev.class = &cxl_class;
 
 	return device_register(&afu->dev);
 }
 
 int cxl_register_adapter(struct cxl *adapter)
 {
-	adapter->dev.class = cxl_class;
+	adapter->dev.class = &cxl_class;
 
 	/*
 	 * Future: When we support dynamically reprogramming the PSL & AFU we
···
 
 	pr_devel("CXL device allocated, MAJOR %i\n", MAJOR(cxl_dev));
 
-	cxl_class = class_create("cxl");
-	if (IS_ERR(cxl_class)) {
+	rc = class_register(&cxl_class);
+	if (rc) {
 		pr_err("Unable to create CXL class\n");
-		rc = PTR_ERR(cxl_class);
 		goto err;
 	}
-	cxl_class->devnode = cxl_devnode;
 
 	return 0;
 
···
 void cxl_file_exit(void)
 {
 	unregister_chrdev_region(cxl_dev, CXL_NUM_MINORS);
-	class_destroy(cxl_class);
+	class_unregister(&cxl_class);
 }