ppdev: make ppdev_class a static const structure

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

Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230620143751.578239-15-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c
index 81ed581..4c188e9 100644 (file)
--- a/drivers/char/ppdev.c
+++ b/drivers/char/ppdev.c
@@ -773,7 +773,9 @@ static __poll_t pp_poll(struct file *file, poll_table *wait)
        return mask;
 }
 
-static struct class *ppdev_class;
+static const struct class ppdev_class = {
+       .name = CHRDEV,
+};
 
 static const struct file_operations pp_fops = {
        .owner          = THIS_MODULE,
@@ -794,7 +796,7 @@ static void pp_attach(struct parport *port)
        if (devices[port->number])
                return;
 
-       ret = device_create(ppdev_class, port->dev,
+       ret = device_create(&ppdev_class, port->dev,
                            MKDEV(PP_MAJOR, port->number), NULL,
                            "parport%d", port->number);
        if (IS_ERR(ret)) {
@@ -810,7 +812,7 @@ static void pp_detach(struct parport *port)
        if (!devices[port->number])
                return;
 
-       device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));
+       device_destroy(&ppdev_class, MKDEV(PP_MAJOR, port->number));
        devices[port->number] = NULL;
 }
 
@@ -841,11 +843,10 @@ static int __init ppdev_init(void)
                pr_warn(CHRDEV ": unable to get major %d\n", PP_MAJOR);
                return -EIO;
        }
-       ppdev_class = class_create(CHRDEV);
-       if (IS_ERR(ppdev_class)) {
-               err = PTR_ERR(ppdev_class);
+       err = class_register(&ppdev_class);
+       if (err)
                goto out_chrdev;
-       }
+
        err = parport_register_driver(&pp_driver);
        if (err < 0) {
                pr_warn(CHRDEV ": unable to register with parport\n");
@@ -856,7 +857,7 @@ static int __init ppdev_init(void)
        goto out;
 
 out_class:
-       class_destroy(ppdev_class);
+       class_unregister(&ppdev_class);
 out_chrdev:
        unregister_chrdev(PP_MAJOR, CHRDEV);
 out:
@@ -867,7 +868,7 @@ static void __exit ppdev_cleanup(void)
 {
        /* Clean up all parport stuff */
        parport_unregister_driver(&pp_driver);
-       class_destroy(ppdev_class);
+       class_unregister(&ppdev_class);
        unregister_chrdev(PP_MAJOR, CHRDEV);
 }