[RFC PATCH 2/3] tty: serial_core: make tty_struct optional

Rob Herring
2016-08-18T01:15:54Z

In order to allow serial drivers to work without a tty, make calls from
drivers and serial_core work when tty_struct is NULL.

Signed-off-by: Rob Herring <robh@kernel.org>
---
drivers/tty/serial/serial_core.c | 3 ++-
drivers/tty/tty_buffer.c | 2 ++
include/linux/serial_core.h | 2 +-
3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 9fc1533..9dd444f 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -111,7 +111,8 @@ void uart_write_wakeup(struct uart_port *port)
* closed. No cookie for you.
*/
BUG_ON(!state);
- tty_wakeup(state->port.tty);
+ if (state->port.tty)
+ tty_wakeup(state->port.tty);
}

static void uart_stop(struct tty_struct *tty)
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index aa80dc9..ffab8ea 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -528,6 +528,8 @@ static void flush_to_ldisc(struct work_struct *work)

void tty_flip_buffer_push(struct tty_port *port)
{
+ if (!port->tty)
+ return;
tty_schedule_flip(port);
}
EXPORT_SYMBOL(tty_flip_buffer_push);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 2f44e20..a27ca1f 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -412,7 +412,7 @@ int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
static inline int uart_tx_stopped(struct uart_port *port)
{
struct tty_struct *tty = port->state->port.tty;
- if (tty->stopped || port->hw_stopped)
+ if ((tty && tty->stopped) || port->hw_stopped)
return 1;
return 0;
}
--
2.9.2