Merge tag 'usb-serial-4.20-rc6' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial into usb-linus

Johan writes:

USB-serial fix for v4.20-rc6

Here's a fix for a reported USB-console regression in 4.18 which
revealed a long-standing bug in the console implementation.

The patch has been in linux-next over night with no reported issues.

Signed-off-by: Johan Hovold <[e-mail]>

* tag 'usb-serial-4.20-rc6' of https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial:
USB: serial: console: fix reported terminal settings

drivers/tty/tty_io.c

···
 	return ERR_PTR(retval);
 }
 
-static void tty_free_termios(struct tty_struct *tty)
+/**
+ * tty_save_termios() - save tty termios data in driver table
+ * @tty: tty whose termios data to save
+ *
+ * Locking: Caller guarantees serialisation with tty_init_termios().
+ */
+void tty_save_termios(struct tty_struct *tty)
 {
 	struct ktermios *tp;
 	int idx = tty->index;
···
 	}
 	*tp = tty->termios;
 }
+EXPORT_SYMBOL_GPL(tty_save_termios);
 
 /**
  *	tty_flush_works		-	flush all works of a tty/pty pair
···
 	WARN_ON(!mutex_is_locked(&tty_mutex));
 	if (tty->ops->shutdown)
 		tty->ops->shutdown(tty);
-	tty_free_termios(tty);
+	tty_save_termios(tty);
 	tty_driver_remove_tty(tty->driver, tty);
 	tty->port->itty = NULL;
 	if (tty->link)

drivers/usb/serial/console.c

···
 		cflag |= PARENB;
 		break;
 	}
-	co->cflag = cflag;
 
 	/*
 	 * no need to check the index here: if the index is wrong, console
···
 			serial->type->set_termios(tty, port, &dummy);
 
 			tty_port_tty_set(&port->port, NULL);
+			tty_save_termios(tty);
 			tty_kref_put(tty);
 		}
 		tty_port_set_initialized(&port->port, 1);

include/linux/tty.h

···
 extern void tty_release_struct(struct tty_struct *tty, int idx);
 extern int tty_release(struct inode *inode, struct file *filp);
 extern void tty_init_termios(struct tty_struct *tty);
+extern void tty_save_termios(struct tty_struct *tty);
 extern int tty_standard_install(struct tty_driver *driver,
 		struct tty_struct *tty);