[SUNZILOG]: Fix locking in cases where UART layer has grabbed the lock already.

drivers/serial/sunzilog.c

@@ -723,36 +723,28 @@ static void sunzilog_start_tx(struct uart_port *port, unsigned int tty_start)
 	}
 }
 
-/* The port lock is not held.  */
+/* The port lock is held.  */
 static void sunzilog_stop_rx(struct uart_port *port)
 {
 	struct uart_sunzilog_port *up = UART_ZILOG(port);
 	struct zilog_channel *channel;
-	unsigned long flags;
 
 	if (ZS_IS_CONS(up))
 		return;
 
-	spin_lock_irqsave(&port->lock, flags);
-
 	channel = ZILOG_CHANNEL_FROM_PORT(port);
 
 	/* Disable all RX interrupts.  */
 	up->curregs[R1] &= ~RxINT_MASK;
 	sunzilog_maybe_update_regs(up, channel);
-
-	spin_unlock_irqrestore(&port->lock, flags);
 }
 
-/* The port lock is not held.  */
+/* The port lock is held.  */
 static void sunzilog_enable_ms(struct uart_port *port)
 {
 	struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;
 	struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
 	unsigned char new_reg;
-	unsigned long flags;
-
-	spin_lock_irqsave(&port->lock, flags);
 
 	new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
 	if (new_reg != up->curregs[R15]) {
@@ -761,8 +753,6 @@ static void sunzilog_enable_ms(struct uart_port *port)
 		/* NOTE: Not subject to 'transmitter active' rule.  */ 
 		write_zsreg(channel, R15, up->curregs[R15]);
 	}
-
-	spin_unlock_irqrestore(&port->lock, flags);
 }
 
 /* The port lock is not held.  */