mxser: call stop_rx from mxser_shutdown_port()

mxser_stop_rx() should be called from mxser_shutdown_port() for several
reasons:
1) info->slock is held while manipulating IER (as on other places),
2) hangup now stops rx too,
3) mxser_close() will use tty_port_close() and there is no place except
   tty_port_operations::shutdown() where this can be done,
4) this is the same sequence as serial_core does. So we can map this
   code 1:1 when switching the driver to it.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20211118073125.12283-9-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 16 insertions, 15 deletions

diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 6b47a0607f59..45ee1122a5f7 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -808,6 +808,20 @@ static int mxser_activate(struct tty_port *port, struct tty_struct *tty)
 }
 
 /*
+ * To stop accepting input, we disable the receive line status interrupts, and
+ * tell the interrupt driver to stop checking the data ready bit in the line
+ * status register.
+ */
+static void mxser_stop_rx(struct mxser_port *info)
+{
+	info->IER &= ~UART_IER_RLSI;
+	if (info->board->must_hwid)
+		info->IER &= ~MOXA_MUST_RECV_ISR;
+
+	outb(info->IER, info->ioaddr + UART_IER);
+}
+
+/*
  * This routine will shutdown a serial port
  */
 static void mxser_shutdown_port(struct tty_port *port)
@@ -817,6 +831,8 @@ static void mxser_shutdown_port(struct tty_port *port)
 
 	spin_lock_irqsave(&info->slock, flags);
 
+	mxser_stop_rx(info);
+
 	/*
 	 * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
 	 * here so the queue might never be waken up
@@ -881,20 +897,6 @@ static void mxser_flush_buffer(struct tty_struct *tty)
 }
 
 /*
- * To stop accepting input, we disable the receive line status interrupts, and
- * tell the interrupt driver to stop checking the data ready bit in the line
- * status register.
- */
-static void mxser_stop_rx(struct mxser_port *info)
-{
-	info->IER &= ~UART_IER_RLSI;
-	if (info->board->must_hwid)
-		info->IER &= ~MOXA_MUST_RECV_ISR;
-
-	outb(info->IER, info->ioaddr + UART_IER);
-}
-
-/*
  * This routine is called when the serial port gets closed.  First, we
  * wait for the last remaining data to be sent.  Then, we unlink its
  * async structure from the interrupt chain if necessary, and we free
@@ -908,7 +910,6 @@ static void mxser_close(struct tty_struct *tty, struct file *filp)
 	if (tty_port_close_start(port, tty, filp) == 0)
 		return;
 	mutex_lock(&port->mutex);
-	mxser_stop_rx(info);
 	mxser_flush_buffer(tty);
 	if (tty_port_initialized(port) && C_HUPCL(tty))
 		tty_port_lower_dtr_rts(port);