s390/3270: fix minor_start issue

The 3270 device nodes 227/0 and 228/0 are special. 227/0 is never used,
and 228/0 is used to redirect full screen applications from /dev/3270/tub
to the real device node of the 3270 terminal.
To keep the device names /dev/3270/tty<x> consistent with the minor number
the device driver sets minor_start to 0 and skips minor 0. That makes the
tty index equivalent to the minor number. But doing so seems to causes
problems with init scripts.
A better solution is to set minor_start to the correct value of 1 and
set name_base to 1 as well. tty_register_device will then automatically
create the correct tty name.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/tty3270.c

@@ -915,7 +915,7 @@ static int tty3270_install(struct tty_driver *driver, struct tty_struct *tty)
 	int i, rc;
 
 	/* Check if the tty3270 is already there. */
-	view = raw3270_find_view(&tty3270_fn, tty->index);
+	view = raw3270_find_view(&tty3270_fn, tty->index + RAW3270_FIRSTMINOR);
 	if (!IS_ERR(view)) {
 		tp = container_of(view, struct tty3270, view);
 		tty->driver_data = tp;
@@ -927,15 +927,16 @@ static int tty3270_install(struct tty_driver *driver, struct tty_struct *tty)
 		tp->inattr = TF_INPUT;
 		return tty_port_install(&tp->port, driver, tty);
 	}
-	if (tty3270_max_index < tty->index)
-		tty3270_max_index = tty->index;
+	if (tty3270_max_index < tty->index + 1)
+		tty3270_max_index = tty->index + 1;
 
 	/* Allocate tty3270 structure on first open. */
 	tp = tty3270_alloc_view();
 	if (IS_ERR(tp))
 		return PTR_ERR(tp);
 
-	rc = raw3270_add_view(&tp->view, &tty3270_fn, tty->index);
+	rc = raw3270_add_view(&tp->view, &tty3270_fn,
+			      tty->index + RAW3270_FIRSTMINOR);
 	if (rc) {
 		tty3270_free_view(tp);
 		return rc;
@@ -1846,12 +1847,12 @@ static const struct tty_operations tty3270_ops = {
 
 void tty3270_create_cb(int minor)
 {
-	tty_register_device(tty3270_driver, minor, NULL);
+	tty_register_device(tty3270_driver, minor - RAW3270_FIRSTMINOR, NULL);
 }
 
 void tty3270_destroy_cb(int minor)
 {
-	tty_unregister_device(tty3270_driver, minor);
+	tty_unregister_device(tty3270_driver, minor - RAW3270_FIRSTMINOR);
 }
 
 struct raw3270_notifier tty3270_notifier =
@@ -1884,7 +1885,8 @@ static int __init tty3270_init(void)
 	driver->driver_name = "tty3270";
 	driver->name = "3270/tty";
 	driver->major = IBM_TTY3270_MAJOR;
-	driver->minor_start = 0;
+	driver->minor_start = RAW3270_FIRSTMINOR;
+	driver->name_base = RAW3270_FIRSTMINOR;
 	driver->type = TTY_DRIVER_TYPE_SYSTEM;
 	driver->subtype = SYSTEM_TYPE_TTY;
 	driver->init_termios = tty_std_termios;