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/include/linux/serial_core.h b/include/linux/serial_core.h
index 452c9cc..204c452 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -197,6 +197,7 @@
 #define UPSTAT_CTS_ENABLE	((__force upstat_t) (1 << 0))
 #define UPSTAT_DCD_ENABLE	((__force upstat_t) (1 << 1))
 
+	int			hw_stopped;		/* sw-assisted CTS flow state */
 	unsigned int		mctrl;			/* current modem ctrl settings */
 	unsigned int		timeout;		/* character-based timeout */
 	unsigned int		type;			/* port type */
@@ -357,7 +358,7 @@
 static inline int uart_tx_stopped(struct uart_port *port)
 {
 	struct tty_struct *tty = port->state->port.tty;
-	if(tty->stopped || tty->hw_stopped)
+	if (tty->stopped || port->hw_stopped)
 		return 1;
 	return 0;
 }