From 4ff4379ce6eefe81695bcc2e021ce1dac3d707d2 Mon Sep 17 00:00:00 2001 From: Florian Eckert Date: Mon, 27 Nov 2023 12:03:08 +0100 Subject: tty: add new helper function tty_get_tiocm There is no in-kernel function to get the status register of a tty device like the TIOCMGET ioctl returns to userspace. Create a new function, tty_get_tiocm(), to obtain the status register that other portions of the kernel can call if they need this information, and move the existing internal tty_tiocmget() function to use this interface. Signed-off-by: Florian Eckert Reviewed-by: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20231127110311.3583957-2-fe@dev.tdt.de Signed-off-by: Lee Jones --- drivers/tty/tty_io.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-) (limited to 'drivers/tty') diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index 06414e43e0b5..e2e93404133e 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -2498,6 +2498,24 @@ static int send_break(struct tty_struct *tty, unsigned int duration) return retval; } +/** + * tty_get_tiocm - get tiocm status register + * @tty: tty device + * + * Obtain the modem status bits from the tty driver if the feature + * is supported. + */ +int tty_get_tiocm(struct tty_struct *tty) +{ + int retval = -ENOTTY; + + if (tty->ops->tiocmget) + retval = tty->ops->tiocmget(tty); + + return retval; +} +EXPORT_SYMBOL_GPL(tty_get_tiocm); + /** * tty_tiocmget - get modem status * @tty: tty device @@ -2510,14 +2528,12 @@ static int send_break(struct tty_struct *tty, unsigned int duration) */ 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_tiocm(tty); + if (retval >= 0) + retval = put_user(retval, p); - if (retval >= 0) - retval = put_user(retval, p); - } return retval; } -- cgit