[PATCH 1/3] TTY: use class_find_device to find port in uart_suspend/resume.

NeilBrown
2015-03-18T06:00:39Z

uart_{suspend,resume}_port seach the children of a uart device
to find a particular tty device.
This requires all the ttys to be direct children of the uart.

A future patch will allow a 'tty_slave' to intervene between
the port and the uart, voiding this requirement.

So change to use class_find_device. This is made possibly by
exporting a "tty_find_device" from tty_io.c

Signed-off-by: NeilBrown <neil@brown.name>
---
drivers/tty/serial/serial_core.c | 21 ++++++++-------------
drivers/tty/tty_io.c | 6 ++++++
include/linux/tty.h | 1 +
3 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 6a1055ae3437..7abb7474870a 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1960,26 +1960,19 @@ struct uart_match {
struct uart_driver *driver;
};

-static int serial_match_port(struct device *dev, void *data)
-{
- struct uart_match *match = data;
- struct tty_driver *tty_drv = match->driver->tty_driver;
- dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
- match->port->line;
-
- return dev->devt == devt; /* Actually, only one tty per port */
-}

int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
{
struct uart_state *state = drv->state + uport->line;
struct tty_port *port = &state->port;
struct device *tty_dev;
- struct uart_match match = {uport, drv};
+ dev_t devt = MKDEV(drv->tty_driver->major,
+ drv->tty_driver->minor_start) +
+ uport->line;

mutex_lock(&port->mutex);

- tty_dev = device_find_child(uport->dev, &match, serial_match_port);
+ tty_dev = tty_find_device(devt);
if (device_may_wakeup(tty_dev)) {
if (!enable_irq_wake(uport->irq))
uport->irq_wake = 1;
@@ -2039,12 +2032,14 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
struct uart_state *state = drv->state + uport->line;
struct tty_port *port = &state->port;
struct device *tty_dev;
- struct uart_match match = {uport, drv};
struct ktermios termios;
+ dev_t devt = MKDEV(drv->tty_driver->major,
+ drv->tty_driver->minor_start) +
+ uport->line;

mutex_lock(&port->mutex);

- tty_dev = device_find_child(uport->dev, &match, serial_match_port);
+ tty_dev = tty_find_device(devt);
if (!uport->suspended && device_may_wakeup(tty_dev)) {
if (uport->irq_wake) {
disable_irq_wake(uport->irq);
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 51f066aa375e..27632ad17d6f 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -3077,6 +3077,12 @@ static struct device *tty_get_device(struct tty_struct *tty)
return class_find_device(tty_class, NULL, &devt, dev_match_devt);
}

+struct device *tty_find_device(dev_t devt)
+{
+ return class_find_device(tty_class, NULL, &devt, dev_match_devt);
+}
+EXPORT_SYMBOL(tty_find_device);
+

/**
* alloc_tty_struct
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 358a337af598..04d5f1213700 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -461,6 +461,7 @@ extern void tty_vhangup(struct tty_struct *tty);
extern int tty_hung_up_p(struct file *filp);
extern void do_SAK(struct tty_struct *tty);
extern void __do_SAK(struct tty_struct *tty);
+extern struct device *tty_find_device(dev_t devt);
extern void no_tty(void);
extern void tty_flush_to_ldisc(struct tty_struct *tty);
extern void tty_buffer_free_all(struct tty_port *port);