serial: core: Privatize tty->hw_stopped

tty->hw_stopped is not used by the tty core and is thread-unsafe;
hw_stopped is a member of a bitfield whose fields are updated
non-atomically and no lock is suitable for serializing updates.

Replace serial core usage of tty->hw_stopped with uport->hw_stopped.
Use int storage which works around Alpha EV4/5 non-atomic byte storage,
since uart_port uses different locks to protect certain fields within the
structure.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/bfin_uart.c b/drivers/tty/serial/bfin_uart.c
index dec0fd7..fc9fbf3 100644
--- a/drivers/tty/serial/bfin_uart.c
+++ b/drivers/tty/serial/bfin_uart.c
@@ -108,22 +108,22 @@
 static irqreturn_t bfin_serial_mctrl_cts_int(int irq, void *dev_id)
 {
 	struct bfin_serial_port *uart = dev_id;
-	unsigned int status = bfin_serial_get_mctrl(&uart->port);
+	struct uart_port *uport = &uart->port;
+	unsigned int status = bfin_serial_get_mctrl(uport);
 #ifdef CONFIG_SERIAL_BFIN_HARD_CTSRTS
-	struct tty_struct *tty = uart->port.state->port.tty;
 
 	UART_CLEAR_SCTS(uart);
-	if (tty->hw_stopped) {
+	if (uport->hw_stopped) {
 		if (status) {
-			tty->hw_stopped = 0;
-			uart_write_wakeup(&uart->port);
+			uport->hw_stopped = 0;
+			uart_write_wakeup(uport);
 		}
 	} else {
 		if (!status)
-			tty->hw_stopped = 1;
+			uport->hw_stopped = 1;
 	}
 #endif
-	uart_handle_cts_change(&uart->port, status & TIOCM_CTS);
+	uart_handle_cts_change(uport, status & TIOCM_CTS);
 
 	return IRQ_HANDLED;
 }