s390/3270: introduce device notifier

Add a notifier to create / destroy the device nodes for the tty view
and the fullscreen view. Only device nodes for online devices are
created and the device names will follow the convention as outlined
in Documentation/devices.txt: 3270/tty<x> for the tty nodes,
3270/tub<x> for hte fullscreen nodes and 3270/tub for the fullscreen
control node.

Signed-off-by: Martin Schwidefsky <[e-mail]>

drivers/s390/char/fs3270.c

···
 			tty_kref_put(tty);
 			return -ENODEV;
 		}
-		minor = tty->index + RAW3270_FIRSTMINOR;
+		minor = tty->index;
 		tty_kref_put(tty);
 	}
 	mutex_lock(&fs3270_mutex);
···
 	.llseek		= no_llseek,
 };
 
+void fs3270_create_cb(int minor)
+{
+	__register_chrdev(IBM_FS3270_MAJOR, minor, 1, "tub", &fs3270_fops);
+	device_create(class3270, NULL, MKDEV(IBM_FS3270_MAJOR, minor),
+		      NULL, "3270/tub%d", minor);
+}
+
+void fs3270_destroy_cb(int minor)
+{
+	device_destroy(class3270, MKDEV(IBM_FS3270_MAJOR, minor));
+	__unregister_chrdev(IBM_FS3270_MAJOR, minor, 1, "tub");
+}
+
+struct raw3270_notifier fs3270_notifier =
+{
+	.create = fs3270_create_cb,
+	.destroy = fs3270_destroy_cb,
+};
+
 /*
  * 3270 fullscreen driver initialization.
  */
···
 {
 	int rc;
 
-	rc = register_chrdev(IBM_FS3270_MAJOR, "fs3270", &fs3270_fops);
+	rc = __register_chrdev(IBM_FS3270_MAJOR, 0, 1, "fs3270", &fs3270_fops);
 	if (rc)
 		return rc;
+	device_create(class3270, NULL, MKDEV(IBM_FS3270_MAJOR, 0),
+		      NULL, "3270/tub");
+	raw3270_register_notifier(&fs3270_notifier);
 	return 0;
 }
 
 static void __exit
 fs3270_exit(void)
 {
-	unregister_chrdev(IBM_FS3270_MAJOR, "fs3270");
+	raw3270_unregister_notifier(&fs3270_notifier);
+	__unregister_chrdev(IBM_FS3270_MAJOR, 0, 1, "fs3270");
 }
 
 MODULE_LICENSE("GPL");

drivers/s390/char/raw3270.c

···
 #include <linux/device.h>
 #include <linux/mutex.h>
 
-static struct class *class3270;
+struct class *class3270;
 
 /* The main 3270 data structure. */
 struct raw3270 {
···
 	struct timer_list timer;	/* Device timer. */
 
 	unsigned char *ascebc;		/* ascii -> ebcdic table */
-	struct device *clttydev;	/* 3270-class tty device ptr */
-	struct device *cltubdev;	/* 3270-class tub device ptr */
 
 	struct raw3270_request init_request;
 	unsigned char init_data[256];
···
 
 	/* Remove from device chain. */
 	mutex_lock(&raw3270_mutex);
-	if (rp->clttydev && !IS_ERR(rp->clttydev))
-		device_destroy(class3270, MKDEV(IBM_TTY3270_MAJOR, rp->minor));
-	if (rp->cltubdev && !IS_ERR(rp->cltubdev))
-		device_destroy(class3270, MKDEV(IBM_FS3270_MAJOR, rp->minor));
 	list_del_init(&rp->list);
 	mutex_unlock(&raw3270_mutex);
 
···
 
 static int raw3270_create_attributes(struct raw3270 *rp)
 {
-	int rc;
-
-	rc = sysfs_create_group(&rp->cdev->dev.kobj, &raw3270_attr_group);
-	if (rc)
-		goto out;
-
-	rp->clttydev = device_create(class3270, &rp->cdev->dev,
-				     MKDEV(IBM_TTY3270_MAJOR, rp->minor), NULL,
-				     "tty%s", dev_name(&rp->cdev->dev));
-	if (IS_ERR(rp->clttydev)) {
-		rc = PTR_ERR(rp->clttydev);
-		goto out_ttydev;
-	}
-
-	rp->cltubdev = device_create(class3270, &rp->cdev->dev,
-				     MKDEV(IBM_FS3270_MAJOR, rp->minor), NULL,
-				     "tub%s", dev_name(&rp->cdev->dev));
-	if (!IS_ERR(rp->cltubdev))
-		goto out;
-
-	rc = PTR_ERR(rp->cltubdev);
-	device_destroy(class3270, MKDEV(IBM_TTY3270_MAJOR, rp->minor));
-
-out_ttydev:
-	sysfs_remove_group(&rp->cdev->dev.kobj, &raw3270_attr_group);
-out:
-	return rc;
+	return sysfs_create_group(&rp->cdev->dev.kobj, &raw3270_attr_group);
 }
 
 /*
  * Notifier for device addition/removal
  */
-struct raw3270_notifier {
-	struct list_head list;
-	void (*notifier)(int, int);
-};
-
 static LIST_HEAD(raw3270_notifier);
 
-int raw3270_register_notifier(void (*notifier)(int, int))
+int raw3270_register_notifier(struct raw3270_notifier *notifier)
 {
-	struct raw3270_notifier *np;
 	struct raw3270 *rp;
 
-	np = kmalloc(sizeof(struct raw3270_notifier), GFP_KERNEL);
-	if (!np)
-		return -ENOMEM;
-	np->notifier = notifier;
 	mutex_lock(&raw3270_mutex);
-	list_add_tail(&np->list, &raw3270_notifier);
-	list_for_each_entry(rp, &raw3270_devices, list) {
-		get_device(&rp->cdev->dev);
-		notifier(rp->minor, 1);
-	}
+	list_add_tail(&notifier->list, &raw3270_notifier);
+	list_for_each_entry(rp, &raw3270_devices, list)
+		notifier->create(rp->minor);
 	mutex_unlock(&raw3270_mutex);
 	return 0;
 }
 
-void raw3270_unregister_notifier(void (*notifier)(int, int))
+void raw3270_unregister_notifier(struct raw3270_notifier *notifier)
 {
-	struct raw3270_notifier *np;
+	struct raw3270 *rp;
 
 	mutex_lock(&raw3270_mutex);
-	list_for_each_entry(np, &raw3270_notifier, list)
-		if (np->notifier == notifier) {
-			list_del(&np->list);
-			kfree(np);
-			break;
-		}
+	list_for_each_entry(rp, &raw3270_devices, list)
+		notifier->destroy(rp->minor);
+	list_del(&notifier->list);
 	mutex_unlock(&raw3270_mutex);
 }
 
···
 static int
 raw3270_set_online (struct ccw_device *cdev)
 {
-	struct raw3270 *rp;
 	struct raw3270_notifier *np;
+	struct raw3270 *rp;
 	int rc;
 
 	rp = raw3270_create_device(cdev);
···
 	set_bit(RAW3270_FLAGS_READY, &rp->flags);
 	mutex_lock(&raw3270_mutex);
 	list_for_each_entry(np, &raw3270_notifier, list)
-		np->notifier(rp->minor, 1);
+		np->create(rp->minor);
 	mutex_unlock(&raw3270_mutex);
 	return 0;
 
···
 
 	mutex_lock(&raw3270_mutex);
 	list_for_each_entry(np, &raw3270_notifier, list)
-		np->notifier(rp->minor, 0);
+		np->destroy(rp->minor);
 	mutex_unlock(&raw3270_mutex);
 
 	/* Reset 3270 device. */
···
 module_init(raw3270_init);
 module_exit(raw3270_exit);
 
+EXPORT_SYMBOL(class3270);
 EXPORT_SYMBOL(raw3270_request_alloc);
 EXPORT_SYMBOL(raw3270_request_free);
 EXPORT_SYMBOL(raw3270_request_reset);

drivers/s390/char/raw3270.h

···
 
 struct raw3270;
 struct raw3270_view;
+extern struct class *class3270;
 
 /* 3270 CCW request */
 struct raw3270_request {
···
 void raw3270_wait_cons_dev(struct raw3270 *);
 
 /* Notifier for device addition/removal */
-int raw3270_register_notifier(void (*notifier)(int, int));
-void raw3270_unregister_notifier(void (*notifier)(int, int));
+struct raw3270_notifier {
+	struct list_head list;
+	void (*create)(int minor);
+	void (*destroy)(int minor);
+};
+
+int raw3270_register_notifier(struct raw3270_notifier *);
+void raw3270_unregister_notifier(struct raw3270_notifier *);
 void raw3270_pm_unfreeze(struct raw3270_view *);
 
 /*

drivers/s390/char/tty3270.c

···
 {
 	int i;
 
-	for (i = 0; i < tty3270_max_index; i++) {
-		struct raw3270_view *view =
-			raw3270_find_view(&tty3270_fn, i + RAW3270_FIRSTMINOR);
+	for (i = RAW3270_FIRSTMINOR; i <= tty3270_max_index; i++) {
+		struct raw3270_view *view = raw3270_find_view(&tty3270_fn, i);
 		if (!IS_ERR(view))
 			raw3270_del_view(view);
 	}
···
 	int i, rc;
 
 	/* Check if the tty3270 is already there. */
-	view = raw3270_find_view(&tty3270_fn,
-				  tty->index + RAW3270_FIRSTMINOR);
+	view = raw3270_find_view(&tty3270_fn, tty->index);
 	if (!IS_ERR(view)) {
 		tp = container_of(view, struct tty3270, view);
 		tty->driver_data = tp;
···
 		tp->inattr = TF_INPUT;
 		return tty_port_install(&tp->port, driver, tty);
 	}
-	if (tty3270_max_index < tty->index + 1)
-		tty3270_max_index = tty->index + 1;
+	if (tty3270_max_index < tty->index)
+		tty3270_max_index = tty->index;
 
 	/* Quick exit if there is no device for tty->index. */
 	if (PTR_ERR(view) == -ENODEV)
···
 	if (IS_ERR(tp))
 		return PTR_ERR(tp);
 
-	rc = raw3270_add_view(&tp->view, &tty3270_fn,
-			      tty->index + RAW3270_FIRSTMINOR);
+	rc = raw3270_add_view(&tp->view, &tty3270_fn, tty->index);
 	if (rc) {
 		tty3270_free_view(tp);
 		return rc;
···
 	.set_termios = tty3270_set_termios
 };
 
+void tty3270_create_cb(int minor)
+{
+	tty_register_device(tty3270_driver, minor, NULL);
+}
+
+void tty3270_destroy_cb(int minor)
+{
+	tty_unregister_device(tty3270_driver, minor);
+}
+
+struct raw3270_notifier tty3270_notifier =
+{
+	.create = tty3270_create_cb,
+	.destroy = tty3270_destroy_cb,
+};
+
 /*
  * 3270 tty registration code called from tty_init().
  * Most kernel services (incl. kmalloc) are available at this poimt.
···
 	struct tty_driver *driver;
 	int ret;
 
-	driver = alloc_tty_driver(RAW3270_MAXDEVS);
-	if (!driver)
-		return -ENOMEM;
+	driver = tty_alloc_driver(RAW3270_MAXDEVS,
+				  TTY_DRIVER_REAL_RAW |
+				  TTY_DRIVER_DYNAMIC_DEV |
+				  TTY_DRIVER_RESET_TERMIOS);
+	if (IS_ERR(driver))
+		return PTR_ERR(driver);
 
 	/*
 	 * Initialize the tty_driver structure
 	 * Entries in tty3270_driver that are NOT initialized:
 	 * proc_entry, set_termios, flush_buffer, set_ldisc, write_proc
 	 */
-	driver->driver_name = "ttyTUB";
-	driver->name = "ttyTUB";
+	driver->driver_name = "tty3270";
+	driver->name = "3270/tty";
 	driver->major = IBM_TTY3270_MAJOR;
-	driver->minor_start = RAW3270_FIRSTMINOR;
+	driver->minor_start = 0;
 	driver->type = TTY_DRIVER_TYPE_SYSTEM;
 	driver->subtype = SYSTEM_TYPE_TTY;
 	driver->init_termios = tty_std_termios;
-	driver->flags = TTY_DRIVER_RESET_TERMIOS;
 	tty_set_operations(driver, &tty3270_ops);
 	ret = tty_register_driver(driver);
 	if (ret) {
···
 		return ret;
 	}
 	tty3270_driver = driver;
+	raw3270_register_notifier(&tty3270_notifier);
 	return 0;
 }
 
···
 {
 	struct tty_driver *driver;
 
+	raw3270_unregister_notifier(&tty3270_notifier);
 	driver = tty3270_driver;
 	tty3270_driver = NULL;
 	tty_unregister_driver(driver);