For tty operations which may expect uart port to have been removed
but still have other necessary work to accomplish, check for NULL
uart port; specifically uart_close(), uart_hangup() and sub-functions
(uart_shutdown() and uart_port_shutdown()).
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 30 ++++++++++++++++++++----------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 1887f9c..d529b5c 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -257,6 +257,8 @@ static int uart_startup(struct tty_struct *tty, struct uart_state *state,
* This routine will shutdown a serial port; interrupts are disabled, and
* DTR is dropped if the hangup on close termio flag is on. Calls to
* uart_shutdown are serialised by the per-port semaphore.
+ *
+ * uport == NULL if uart_port has already been removed
*/
static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
{
@@ -275,7 +277,7 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
/*
* Turn off DTR and RTS early.
*/
- if (uart_console(uport) && tty)
+ if (uport && uart_console(uport) && tty)
uport->cons->cflag = tty->termios.c_cflag;
if (!tty || C_HUPCL(tty))
@@ -1460,7 +1462,6 @@ out:
* Calls to uart_close() are serialised via the tty_lock in
* drivers/tty/tty_io.c:tty_release()
* drivers/tty/tty_io.c:do_tty_hangup()
- * This runs from a workqueue and can sleep for a _short_ time only.
*/
static void uart_close(struct tty_struct *tty, struct file *filp)
{
@@ -1479,18 +1480,21 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
return;
}
- uport = state->uart_port;
port = &state->port;
pr_debug("uart_close(%d) called\n", tty->index);
- if (!port->count || tty_port_close_start(port, tty, filp) == 0)
+ if (tty_port_close_start(port, tty, filp) == 0)
return;
+ mutex_lock(&port->mutex);
+ uport = uart_port_check(state);
+
/*
* At this point, we stop accepting input. To do this, we
* disable the receive line status interrupts.
*/
- if (tty_port_initialized(port)) {
+ if (tty_port_initialized(port) &&
+ !WARN(!uport, "detached port still initialized!\n")) {
spin_lock_irq(&uport->lock);
uport->ops->stop_rx(uport);
spin_unlock_irq(&uport->lock);
@@ -1502,7 +1506,6 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
uart_wait_until_sent(tty, uport->timeout);
}
- mutex_lock(&port->mutex);
uart_shutdown(tty, state);
tty_port_tty_set(port, NULL);
@@ -1513,7 +1516,7 @@ static void uart_close(struct tty_struct *tty, struct file *filp)
if (port->close_delay)
msleep_interruptible(jiffies_to_msecs(port->close_delay));
spin_lock_irq(&port->lock);
- } else if (!uart_console(uport)) {
+ } else if (uport && !uart_console(uport)) {
spin_unlock_irq(&port->lock);
uart_change_pm(state, UART_PM_STATE_OFF);
spin_lock_irq(&port->lock);
@@ -1600,11 +1603,15 @@ static void uart_hangup(struct tty_struct *tty)
{
struct uart_state *state = tty->driver_data;
struct tty_port *port = &state->port;
+ struct uart_port *uport;
unsigned long flags;
pr_debug("uart_hangup(%d)\n", tty->index);
mutex_lock(&port->mutex);
+ uport = uart_port_check(state);
+ WARN(!uport, "hangup of detached port!\n");
+
if (tty_port_active(port)) {
uart_flush_buffer(tty);
uart_shutdown(tty, state);
@@ -1613,7 +1620,7 @@ static void uart_hangup(struct tty_struct *tty)
spin_unlock_irqrestore(&port->lock, flags);
tty_port_set_active(port, 0);
tty_port_tty_set(port, NULL);
- if (!uart_console(state->uart_port))
+ if (uport && !uart_console(uport))
uart_change_pm(state, UART_PM_STATE_OFF);
wake_up_interruptible(&port->open_wait);
wake_up_interruptible(&port->delta_msr_wait);
@@ -1621,6 +1628,7 @@ static void uart_hangup(struct tty_struct *tty)
mutex_unlock(&port->mutex);
}
+/* uport == NULL if uart_port has already been removed */
static void uart_port_shutdown(struct tty_port *port)
{
struct uart_state *state = container_of(port, struct uart_state, port);
@@ -1638,12 +1646,14 @@ static void uart_port_shutdown(struct tty_port *port)
/*
* Free the IRQ and disable the port.
*/
- uport->ops->shutdown(uport);
+ if (uport)
+ uport->ops->shutdown(uport);
/*
* Ensure that the IRQ handler isn't running on another CPU.
*/
- synchronize_irq(uport->irq);
+ if (uport)
+ synchronize_irq(uport->irq);
}
static int uart_carrier_raised(struct tty_port *port)
--
2.8.1
--
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