tty: mxser: Remove ASYNC_CLOSING

The tty core no longer provides ASYNC_CLOSING. Use private flag for
same purpose, which is to clear the fifos at each and every interrupt
during driver close(). The driver uses this sledgehammer approach because
its close/shutdown sequence is hopelessly borked.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/mxser.c

@@ -254,6 +254,7 @@ struct mxser_port {
 	int xmit_head;
 	int xmit_tail;
 	int xmit_cnt;
+	int closing;
 
 	struct ktermios normal_termios;
 
@@ -1081,6 +1082,7 @@ static void mxser_close(struct tty_struct *tty, struct file *filp)
 		return;
 	if (tty_port_close_start(port, tty, filp) == 0)
 		return;
+	info->closing = 1;
 	mutex_lock(&port->mutex);
 	mxser_close_port(port);
 	mxser_flush_buffer(tty);
@@ -1091,6 +1093,7 @@ static void mxser_close(struct tty_struct *tty, struct file *filp)
 	mxser_shutdown_port(port);
 	clear_bit(ASYNCB_INITIALIZED, &port->flags);
 	mutex_unlock(&port->mutex);
+	info->closing = 0;
 	/* Right now the tty_port set is done outside of the close_end helper
 	   as we don't yet have everyone using refcounts */	
 	tty_port_close_end(port, tty);
@@ -2253,10 +2256,8 @@ static irqreturn_t mxser_interrupt(int irq, void *dev_id)
 					break;
 				iir &= MOXA_MUST_IIR_MASK;
 				tty = tty_port_tty_get(&port->port);
-				if (!tty ||
-						(port->port.flags & ASYNC_CLOSING) ||
-						!(port->port.flags &
-							ASYNC_INITIALIZED)) {
+				if (!tty || port->closing ||
+				    !(port->port.flags & ASYNC_INITIALIZED)) {
 					status = inb(port->ioaddr + UART_LSR);
 					outb(0x27, port->ioaddr + UART_FCR);
 					inb(port->ioaddr + UART_MSR);