tty: Make ->set_termios() old ktermios const

There should be no reason to adjust old ktermios which is going to get
discarded anyway.
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220816115739.10928-9-ilpo.jarvinen@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/pcmcia/synclink_cs.c

@@ -2274,7 +2274,8 @@ static int mgslpc_ioctl(struct tty_struct *tty,
  *	tty		pointer to tty structure
  *	termios		pointer to buffer to hold returned old termios
  */
-static void mgslpc_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
+static void mgslpc_set_termios(struct tty_struct *tty,
+			       const struct ktermios *old_termios)
 {
 	MGSLPC_INFO *info = (MGSLPC_INFO *)tty->driver_data;
 	unsigned long flags;

drivers/ipack/devices/ipoctal.c

@@ -497,7 +497,7 @@ static unsigned int ipoctal_chars_in_buffer(struct tty_struct *tty)
 }
 
 static void ipoctal_set_termios(struct tty_struct *tty,
-				struct ktermios *old_termios)
+				const struct ktermios *old_termios)
 {
 	unsigned int cflag;
 	unsigned char mr1 = 0;

drivers/mmc/core/sdio_uart.c

@@ -246,7 +246,7 @@ static inline void sdio_uart_update_mctrl(struct sdio_uart_port *port,
 
 static void sdio_uart_change_speed(struct sdio_uart_port *port,
 				   struct ktermios *termios,
-				   struct ktermios *old)
+				   const struct ktermios *old)
 {
 	unsigned char cval, fcr = 0;
 	unsigned int baud, quot;
@@ -859,7 +859,7 @@ static void sdio_uart_unthrottle(struct tty_struct *tty)
 }
 
 static void sdio_uart_set_termios(struct tty_struct *tty,
-						struct ktermios *old_termios)
+				  const struct ktermios *old_termios)
 {
 	struct sdio_uart_port *port = tty->driver_data;
 	unsigned int cflag = tty->termios.c_cflag;

drivers/net/usb/hso.c

@@ -1380,7 +1380,8 @@ static void hso_serial_cleanup(struct tty_struct *tty)
 }
 
 /* setup the term */
-static void hso_serial_set_termios(struct tty_struct *tty, struct ktermios *old)
+static void hso_serial_set_termios(struct tty_struct *tty,
+				   const struct ktermios *old)
 {
 	struct hso_serial *serial = tty->driver_data;
 	unsigned long flags;

drivers/s390/char/tty3270.c

@@ -1760,7 +1760,7 @@ tty3270_flush_chars(struct tty_struct *tty)
  * Check for visible/invisible input switches
  */
 static void
-tty3270_set_termios(struct tty_struct *tty, struct ktermios *old)
+tty3270_set_termios(struct tty_struct *tty, const struct ktermios *old)
 {
 	struct tty3270 *tp;
 	int new;

drivers/staging/fwserial/fwserial.c

@@ -1267,7 +1267,8 @@ static int fwtty_ioctl(struct tty_struct *tty, unsigned int cmd,
 	return err;
 }
 
-static void fwtty_set_termios(struct tty_struct *tty, struct ktermios *old)
+static void fwtty_set_termios(struct tty_struct *tty,
+			      const struct ktermios *old)
 {
 	struct fwtty_port *port = tty->driver_data;
 	unsigned int baud;

drivers/staging/greybus/uart.c

@@ -480,7 +480,7 @@ static int gb_tty_break_ctl(struct tty_struct *tty, int state)
 }
 
 static void gb_tty_set_termios(struct tty_struct *tty,
-			       struct ktermios *termios_old)
+			       const struct ktermios *termios_old)
 {
 	struct gb_uart_set_line_coding_request newline;
 	struct gb_tty *gb_tty = tty->driver_data;

drivers/tty/amiserial.c

@@ -94,7 +94,7 @@ static struct tty_driver *serial_driver;
 static unsigned char current_ctl_bits;
 
 static void change_speed(struct tty_struct *tty, struct serial_state *info,
-		struct ktermios *old);
+			 const struct ktermios *old);
 static void rs_wait_until_sent(struct tty_struct *tty, int timeout);
 
 
@@ -566,7 +566,7 @@ static void shutdown(struct tty_struct *tty, struct serial_state *info)
  * the specified baud rate for a serial port.
  */
 static void change_speed(struct tty_struct *tty, struct serial_state *info,
-			 struct ktermios *old_termios)
+			 const struct ktermios *old_termios)
 {
 	struct tty_port *port = &info->tport;
 	int	quot = 0, baud_base, baud;
@@ -1169,7 +1169,7 @@ static int rs_ioctl(struct tty_struct *tty,
 	return 0;
 }
 
-static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
+static void rs_set_termios(struct tty_struct *tty, const struct ktermios *old_termios)
 {
 	struct serial_state *info = tty->driver_data;
 	unsigned long flags;

drivers/tty/moxa.c

@@ -491,7 +491,7 @@ static int moxa_write(struct tty_struct *, const unsigned char *, int);
 static unsigned int moxa_write_room(struct tty_struct *);
 static void moxa_flush_buffer(struct tty_struct *);
 static unsigned int moxa_chars_in_buffer(struct tty_struct *);
-static void moxa_set_termios(struct tty_struct *, struct ktermios *);
+static void moxa_set_termios(struct tty_struct *, const struct ktermios *);
 static void moxa_stop(struct tty_struct *);
 static void moxa_start(struct tty_struct *);
 static void moxa_hangup(struct tty_struct *);
@@ -499,7 +499,7 @@ static int moxa_tiocmget(struct tty_struct *tty);
 static int moxa_tiocmset(struct tty_struct *tty,
 			 unsigned int set, unsigned int clear);
 static void moxa_poll(struct timer_list *);
-static void moxa_set_tty_param(struct tty_struct *, struct ktermios *);
+static void moxa_set_tty_param(struct tty_struct *, const struct ktermios *);
 static void moxa_shutdown(struct tty_port *);
 static int moxa_carrier_raised(struct tty_port *);
 static void moxa_dtr_rts(struct tty_port *, int);
@@ -1602,7 +1602,7 @@ static int moxa_tiocmset(struct tty_struct *tty,
 }
 
 static void moxa_set_termios(struct tty_struct *tty,
-		struct ktermios *old_termios)
+		             const struct ktermios *old_termios)
 {
 	struct moxa_port *ch = tty->driver_data;
 
@@ -1761,7 +1761,8 @@ static void moxa_poll(struct timer_list *unused)
 
 /******************************************************************************/
 
-static void moxa_set_tty_param(struct tty_struct *tty, struct ktermios *old_termios)
+static void moxa_set_tty_param(struct tty_struct *tty,
+			       const struct ktermios *old_termios)
 {
 	register struct ktermios *ts = &tty->termios;
 	struct moxa_port *ch = tty->driver_data;

drivers/tty/mxser.c

@@ -571,7 +571,8 @@ static void mxser_handle_cts(struct tty_struct *tty, struct mxser_port *info,
  * This routine is called to set the UART divisor registers to match
  * the specified baud rate for a serial port.
  */
-static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_termios)
+static void mxser_change_speed(struct tty_struct *tty,
+			       const struct ktermios *old_termios)
 {
 	struct mxser_port *info = tty->driver_data;
 	unsigned cflag, cval;
@@ -1348,7 +1349,8 @@ static void mxser_start(struct tty_struct *tty)
 	spin_unlock_irqrestore(&info->slock, flags);
 }
 
-static void mxser_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
+static void mxser_set_termios(struct tty_struct *tty,
+			      const struct ktermios *old_termios)
 {
 	struct mxser_port *info = tty->driver_data;
 	unsigned long flags;

drivers/tty/n_gsm.c

@@ -3647,7 +3647,8 @@ static int gsmtty_ioctl(struct tty_struct *tty,
 	}
 }
 
-static void gsmtty_set_termios(struct tty_struct *tty, struct ktermios *old)
+static void gsmtty_set_termios(struct tty_struct *tty,
+			       const struct ktermios *old)
 {
 	struct gsm_dlci *dlci = tty->driver_data;
 	if (dlci->state == DLCI_CLOSED)

drivers/tty/pty.c

@@ -240,7 +240,7 @@ static int pty_open(struct tty_struct *tty, struct file *filp)
 }
 
 static void pty_set_termios(struct tty_struct *tty,
-					struct ktermios *old_termios)
+			    const struct ktermios *old_termios)
 {
 	/* See if packet mode change of state. */
 	if (tty->link && tty->link->ctrl.packet) {

drivers/tty/serial/serial_core.c

@@ -49,7 +49,7 @@ static struct lock_class_key port_lock_key;
 #define RS485_MAX_RTS_DELAY	100 /* msecs */
 
 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
-					struct ktermios *old_termios);
+			      const struct ktermios *old_termios);
 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
 static void uart_change_pm(struct uart_state *state,
 			   enum uart_pm_state pm_state);
@@ -492,7 +492,7 @@ EXPORT_SYMBOL(uart_get_divisor);
 
 /* Caller holds port mutex */
 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
-					struct ktermios *old_termios)
+			      const struct ktermios *old_termios)
 {
 	struct uart_port *uport = uart_port_check(state);
 	struct ktermios *termios;
@@ -1619,7 +1619,7 @@ static void uart_set_ldisc(struct tty_struct *tty)
 }
 
 static void uart_set_termios(struct tty_struct *tty,
-						struct ktermios *old_termios)
+			     const struct ktermios *old_termios)
 {
 	struct uart_state *state = tty->driver_data;
 	struct uart_port *uport;

drivers/tty/synclink_gt.c

@@ -707,7 +707,8 @@ static void hangup(struct tty_struct *tty)
 	wake_up_interruptible(&info->port.open_wait);
 }
 
-static void set_termios(struct tty_struct *tty, struct ktermios *old_termios)
+static void set_termios(struct tty_struct *tty,
+			const struct ktermios *old_termios)
 {
 	struct slgt_info *info = tty->driver_data;
 	unsigned long flags;

drivers/usb/class/cdc-acm.c

@@ -51,7 +51,7 @@ static DEFINE_IDR(acm_minors);
 static DEFINE_MUTEX(acm_minors_lock);
 
 static void acm_tty_set_termios(struct tty_struct *tty,
-				struct ktermios *termios_old);
+				const struct ktermios *termios_old);
 
 /*
  * acm_minors accessors
@@ -1049,7 +1049,7 @@ static int acm_tty_ioctl(struct tty_struct *tty,
 }
 
 static void acm_tty_set_termios(struct tty_struct *tty,
-						struct ktermios *termios_old)
+				const struct ktermios *termios_old)
 {
 	struct acm *acm = tty->driver_data;
 	struct ktermios *termios = &tty->termios;

drivers/usb/serial/usb-serial.c

@@ -519,7 +519,8 @@ static int serial_ioctl(struct tty_struct *tty,
 	return retval;
 }
 
-static void serial_set_termios(struct tty_struct *tty, struct ktermios *old)
+static void serial_set_termios(struct tty_struct *tty,
+		               const struct ktermios *old)
 {
 	struct usb_serial_port *port = tty->driver_data;
 

include/linux/tty_driver.h

@@ -141,7 +141,7 @@ struct serial_struct;
  *
  *	Optional.
  *
- * @set_termios: ``void ()(struct tty_struct *tty, struct ktermios *old)``
+ * @set_termios: ``void ()(struct tty_struct *tty, const struct ktermios *old)``
  *
  *	This routine allows the @tty driver to be notified when device's
  *	termios settings have changed. New settings are in @tty->termios.
@@ -365,7 +365,7 @@ struct tty_operations {
 		    unsigned int cmd, unsigned long arg);
 	long (*compat_ioctl)(struct tty_struct *tty,
 			     unsigned int cmd, unsigned long arg);
-	void (*set_termios)(struct tty_struct *tty, struct ktermios * old);
+	void (*set_termios)(struct tty_struct *tty, const struct ktermios *old);
 	void (*throttle)(struct tty_struct * tty);
 	void (*unthrottle)(struct tty_struct * tty);
 	void (*stop)(struct tty_struct *tty);

net/bluetooth/rfcomm/tty.c

@@ -855,7 +855,8 @@ static int rfcomm_tty_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned l
 	return -ENOIOCTLCMD;
 }
 
-static void rfcomm_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
+static void rfcomm_tty_set_termios(struct tty_struct *tty,
+				   const struct ktermios *old)
 {
 	struct ktermios *new = &tty->termios;
 	int old_baud_rate = tty_termios_baud_rate(old);