Re: [PATCH 1/3] serdev: ttyport: make use of tty_kopen_exclusive

Jiri Slaby
2024-08-08T07:51:59Z

On 07. 08. 24, 16:08, Marco Felsch wrote:
> The purpose of serdev is to provide kernel drivers for particular serial
> device, serdev-ttyport is no exception here. Make use of the
> tty_kopen_exclusive() funciton to mark this tty device as kernel
> internal device.
>
> Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
> ---
> drivers/tty/serdev/serdev-ttyport.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
> index 3d7ae7fa5018..94c43d25ddbe 100644
> --- a/drivers/tty/serdev/serdev-ttyport.c
> +++ b/drivers/tty/serdev/serdev-ttyport.c
> @@ -103,11 +103,14 @@ static int ttyport_write_room(struct serdev_controller *ctrl)
> static int ttyport_open(struct serdev_controller *ctrl)
> {
> struct serport *serport = serdev_controller_get_drvdata(ctrl);
> + struct tty_driver *tty_drv = serport->tty_drv;
> struct tty_struct *tty;
> struct ktermios ktermios;
> + dev_t dev;
> int ret;
>
> - tty = tty_init_dev(serport->tty_drv, serport->tty_idx);
> + dev = MKDEV(tty_drv->major, tty_drv->minor_start + serport->tty_idx);
> + tty = tty_kopen_exclusive(dev);

I believe that the now added tty_lookup_driver() has negligible impact
in this anyway slow path, right?

thanks,
--
js
suse labs