comedi: make all 'class' structures const

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

Cc: Ian Abbott <abbotti@mev.co.uk>
Cc: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Ivan Orlov <ivan.orlov0322@gmail.com>
Cc: Xuezhi Zhang <zhangxuezhi1@coolpad.com>
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ivan Orlov <ivan.orlov0322@gmail.com>
Link: https://lore.kernel.org/r/20230620144137.581406-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/comedi/comedi_fops.c b/drivers/comedi/comedi_fops.c
index 8e43918..1548dea 100644 (file)
--- a/drivers/comedi/comedi_fops.c
+++ b/drivers/comedi/comedi_fops.c
@@ -97,7 +97,6 @@ static DEFINE_MUTEX(comedi_subdevice_minor_table_lock);
 static struct comedi_subdevice
 *comedi_subdevice_minor_table[COMEDI_NUM_SUBDEVICE_MINORS];
 
-static struct class *comedi_class;
 static struct cdev comedi_cdev;
 
 static void comedi_device_init(struct comedi_device *dev)
@@ -187,18 +186,6 @@ static struct comedi_device *comedi_clear_board_minor(unsigned int minor)
        return dev;
 }
 
-static void comedi_free_board_dev(struct comedi_device *dev)
-{
-       if (dev) {
-               comedi_device_cleanup(dev);
-               if (dev->class_dev) {
-                       device_destroy(comedi_class,
-                                      MKDEV(COMEDI_MAJOR, dev->minor));
-               }
-               comedi_dev_put(dev);
-       }
-}
-
 static struct comedi_subdevice *
 comedi_subdevice_from_minor(const struct comedi_device *dev, unsigned int minor)
 {
@@ -611,6 +598,23 @@ static struct attribute *comedi_dev_attrs[] = {
 };
 ATTRIBUTE_GROUPS(comedi_dev);
 
+static const struct class comedi_class = {
+       .name = "comedi",
+       .dev_groups = comedi_dev_groups,
+};
+
+static void comedi_free_board_dev(struct comedi_device *dev)
+{
+       if (dev) {
+               comedi_device_cleanup(dev);
+               if (dev->class_dev) {
+                       device_destroy(&comedi_class,
+                                      MKDEV(COMEDI_MAJOR, dev->minor));
+               }
+               comedi_dev_put(dev);
+       }
+}
+
 static void __comedi_clear_subdevice_runflags(struct comedi_subdevice *s,
                                              unsigned int bits)
 {
@@ -3263,7 +3267,7 @@ struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device)
                return ERR_PTR(-EBUSY);
        }
        dev->minor = i;
-       csdev = device_create(comedi_class, hardware_device,
+       csdev = device_create(&comedi_class, hardware_device,
                              MKDEV(COMEDI_MAJOR, i), NULL, "comedi%i", i);
        if (!IS_ERR(csdev))
                dev->class_dev = get_device(csdev);
@@ -3312,7 +3316,7 @@ int comedi_alloc_subdevice_minor(struct comedi_subdevice *s)
        }
        i += COMEDI_NUM_BOARD_MINORS;
        s->minor = i;
-       csdev = device_create(comedi_class, dev->class_dev,
+       csdev = device_create(&comedi_class, dev->class_dev,
                              MKDEV(COMEDI_MAJOR, i), NULL, "comedi%i_subd%i",
                              dev->minor, s->index);
        if (!IS_ERR(csdev))
@@ -3337,7 +3341,7 @@ void comedi_free_subdevice_minor(struct comedi_subdevice *s)
                comedi_subdevice_minor_table[i] = NULL;
        mutex_unlock(&comedi_subdevice_minor_table_lock);
        if (s->class_dev) {
-               device_destroy(comedi_class, MKDEV(COMEDI_MAJOR, s->minor));
+               device_destroy(&comedi_class, MKDEV(COMEDI_MAJOR, s->minor));
                s->class_dev = NULL;
        }
 }
@@ -3383,15 +3387,12 @@ static int __init comedi_init(void)
        if (retval)
                goto out_unregister_chrdev_region;
 
-       comedi_class = class_create("comedi");
-       if (IS_ERR(comedi_class)) {
-               retval = PTR_ERR(comedi_class);
+       retval = class_register(&comedi_class);
+       if (retval) {
                pr_err("failed to create class\n");
                goto out_cdev_del;
        }
 
-       comedi_class->dev_groups = comedi_dev_groups;
-
        /* create devices files for legacy/manual use */
        for (i = 0; i < comedi_num_legacy_minors; i++) {
                struct comedi_device *dev;
@@ -3413,7 +3414,7 @@ static int __init comedi_init(void)
 
 out_cleanup_board_minors:
        comedi_cleanup_board_minors();
-       class_destroy(comedi_class);
+       class_unregister(&comedi_class);
 out_cdev_del:
        cdev_del(&comedi_cdev);
 out_unregister_chrdev_region:
@@ -3425,7 +3426,7 @@ module_init(comedi_init);
 static void __exit comedi_cleanup(void)
 {
        comedi_cleanup_board_minors();
-       class_destroy(comedi_class);
+       class_unregister(&comedi_class);
        cdev_del(&comedi_cdev);
        unregister_chrdev_region(MKDEV(COMEDI_MAJOR, 0), COMEDI_NUM_MINORS);
 

diff --git a/drivers/comedi/drivers/comedi_test.c b/drivers/comedi/drivers/comedi_test.c
index c02dc19..30ea8b5 100644 (file)
--- a/drivers/comedi/drivers/comedi_test.c
+++ b/drivers/comedi/drivers/comedi_test.c
@@ -60,7 +60,9 @@
 static bool config_mode;
 static unsigned int set_amplitude;
 static unsigned int set_period;
-static struct class *ctcls;
+static const struct class ctcls = {
+       .name = CLASS_NAME,
+};
 static struct device *ctdev;
 
 module_param_named(noauto, config_mode, bool, 0444);
@@ -795,13 +797,13 @@ static int __init comedi_test_init(void)
        }
 
        if (!config_mode) {
-               ctcls = class_create(CLASS_NAME);
-               if (IS_ERR(ctcls)) {
+               ret = class_register(&ctcls);
+               if (ret) {
                        pr_warn("comedi_test: unable to create class\n");
                        goto clean3;
                }
 
-               ctdev = device_create(ctcls, NULL, MKDEV(0, 0), NULL, DEV_NAME);
+               ctdev = device_create(&ctcls, NULL, MKDEV(0, 0), NULL, DEV_NAME);
                if (IS_ERR(ctdev)) {
                        pr_warn("comedi_test: unable to create device\n");
                        goto clean2;
@@ -817,13 +819,10 @@ static int __init comedi_test_init(void)
        return 0;
 
 clean:
-       device_destroy(ctcls, MKDEV(0, 0));
+       device_destroy(&ctcls, MKDEV(0, 0));
 clean2:
-       class_destroy(ctcls);
-       ctdev = NULL;
+       class_unregister(&ctcls);
 clean3:
-       ctcls = NULL;
-
        return 0;
 }
 module_init(comedi_test_init);
@@ -833,9 +832,9 @@ static void __exit comedi_test_exit(void)
        if (ctdev)
                comedi_auto_unconfig(ctdev);
 
-       if (ctcls) {
-               device_destroy(ctcls, MKDEV(0, 0));
-               class_destroy(ctcls);
+       if (class_is_registered(&ctcls)) {
+               device_destroy(&ctcls, MKDEV(0, 0));
+               class_unregister(&ctcls);
        }
 
        comedi_driver_unregister(&waveform_driver);