[PATCH 1/2] tty: new helper function tty_get_mget

Florian Eckert
2023-02-13T14:33:01Z

For a given struct tty_struct, this provides the appropriate tty line
state flags needed to add more modes to the ledtrig-tty trigger.

The new function is then used to get via tty_tiocmget() the different tty
line states.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
---
drivers/tty/tty_io.c | 32 +++++++++++++++++++++++++-------
include/linux/tty.h | 3 ++-
2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 3149114bf130..e4dc59eda43f 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2493,26 +2493,44 @@ static int send_break(struct tty_struct *tty, unsigned int duration)
return retval;
}

+/*
+ * tty_get_mget - get modem status
+ * @tty: tty device
+ *
+ * Obtain the modem status bits from the tty driver if the feature
+ * is supported. Return -ENOTTY if it is not available.
+ *
+ */
+
+int tty_get_mget(struct tty_struct *tty)
+{
+ int retval = -ENOTTY;
+
+ if (tty->ops->tiocmget)
+ retval = tty->ops->tiocmget(tty);
+
+ return retval;
+}
+EXPORT_SYMBOL_GPL(tty_get_mget);
+
/**
* tty_tiocmget - get modem status
* @tty: tty device
* @p: pointer to result
*
* Obtain the modem status bits from the tty driver if the feature is
- * supported. Return -%ENOTTY if it is not available.
+ * supported.
*
* Locking: none (up to the driver)
*/
static int tty_tiocmget(struct tty_struct *tty, int __user *p)
{
- int retval = -ENOTTY;
+ int retval;

- if (tty->ops->tiocmget) {
- retval = tty->ops->tiocmget(tty);
+ retval = tty_get_mget(tty);
+ if (retval >= 0)
+ retval = put_user(retval, p);

- if (retval >= 0)
- retval = put_user(retval, p);
- }
return retval;
}

diff --git a/include/linux/tty.h b/include/linux/tty.h
index 730c3301d710..9c1485c31081 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -419,8 +419,9 @@ void tty_unthrottle(struct tty_struct *tty);
int tty_throttle_safe(struct tty_struct *tty);
int tty_unthrottle_safe(struct tty_struct *tty);
int tty_do_resize(struct tty_struct *tty, struct winsize *ws);
-int tty_get_icount(struct tty_struct *tty,
+int tty_get_icount(struct tty_struct *tty
struct serial_icounter_struct *icount);
+extern int tty_get_mget(struct tty_struct *tty);
int is_current_pgrp_orphaned(void);
void tty_hangup(struct tty_struct *tty);
void tty_vhangup(struct tty_struct *tty);
--
2.30.2