tty/serial: lay the foundations for the next set of reworks

- Stop drivers calling their own flush method indirectly, it obfuscates code
  and it will change soon anyway

- A few more lock_kernel paths temporarily needed in some driver internal
  waiting code

- Remove private put_char method that does a write call for one char - we
  have that anyway

- Most but not yet all of the termios copy under lock fixing (some has other
  dependencies to follow)

- Note a few locking bugs in drivers found in the process

- Kill remaining [ab]users of TIOCG/SSOFTCAR in the driver, these must go to
  fix the termios locking

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/68328serial.c

@@ -1017,18 +1017,6 @@ static int rs_ioctl(struct tty_struct *tty, struct file * file,
 			tty_wait_until_sent(tty, 0);
 			send_break(info, arg ? arg*(100) : 250);
 			return 0;
-		case TIOCGSOFTCAR:
-			error = put_user(C_CLOCAL(tty) ? 1 : 0,
-				    (unsigned long *) arg);
-			if (error)
-				return error;
-			return 0;
-		case TIOCSSOFTCAR:
-			get_user(arg, (unsigned long *) arg);
-			tty->termios->c_cflag =
-				((tty->termios->c_cflag & ~CLOCAL) |
-				 (arg ? CLOCAL : 0));
-			return 0;
 		case TIOCGSERIAL:
 			if (access_ok(VERIFY_WRITE, (void *) arg,
 						sizeof(struct serial_struct)))
@@ -1061,9 +1049,6 @@ static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
 {
 	struct m68k_serial *info = (struct m68k_serial *)tty->driver_data;
 
-	if (tty->termios->c_cflag == old_termios->c_cflag)
-		return;
-
 	change_speed(info);
 
 	if ((old_termios->c_cflag & CRTSCTS) &&
@@ -1140,8 +1125,7 @@ static void rs_close(struct tty_struct *tty, struct file * filp)
 	uart->ustcnt &= ~(USTCNT_RXEN | USTCNT_RX_INTR_MASK);
 
 	shutdown(info);
-	if (tty->driver->flush_buffer)
-		tty->driver->flush_buffer(tty);
+	rs_flush_buffer(tty);
 		
 	tty_ldisc_flush(tty);
 	tty->closing = 0;