oradax: make 'cl' a static const structure

Now that the driver core allows for struct class to be in read-only
memory, move the 'cl' structure to be declared at build time
placing it into read-only memory, instead of having to be dynamically
allocated at load time.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Ivan Orlov <ivan.orlov0322@gmail.com>
Cc: sparclinux@vger.kernel.org
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/20230620183446.684061-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: ivanorlov2206

drivers/sbus/char/oradax.c

@@ -226,8 +226,10 @@ static int dax_ccb_info(u64 ca, struct ccb_info_result *info);
 static int dax_ccb_kill(u64 ca, u16 *kill_res);
 
 static struct cdev c_dev;
-static struct class *cl;
 static dev_t first;
+static const struct class cl = {
+	.name = DAX_NAME,
+};
 
 static int max_ccb_version;
 static int dax_debug;
@@ -323,14 +325,11 @@ static int __init dax_attach(void)
 		goto done;
 	}
 
-	cl = class_create(DAX_NAME);
-	if (IS_ERR(cl)) {
-		dax_err("class_create failed");
-		ret = PTR_ERR(cl);
+	ret = class_register(&cl);
+	if (ret)
 		goto class_error;
-	}
 
-	if (device_create(cl, NULL, first, NULL, dax_name) == NULL) {
+	if (device_create(&cl, NULL, first, NULL, dax_name) == NULL) {
 		dax_err("device_create failed");
 		ret = -ENXIO;
 		goto device_error;
@@ -347,9 +346,9 @@ static int __init dax_attach(void)
 	goto done;
 
 cdev_error:
-	device_destroy(cl, first);
+	device_destroy(&cl, first);
 device_error:
-	class_destroy(cl);
+	class_unregister(&cl);
 class_error:
 	unregister_chrdev_region(first, 1);
 done:
@@ -362,8 +361,8 @@ static void __exit dax_detach(void)
 {
 	pr_info("Cleaning up DAX module\n");
 	cdev_del(&c_dev);
-	device_destroy(cl, first);
-	class_destroy(cl);
+	device_destroy(&cl, first);
+	class_unregister(&cl);
 	unregister_chrdev_region(first, 1);
 }
 module_exit(dax_detach);