diff mbox series

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

Message ID 20240807-v6-10-topic-usb-serial-serdev-v1-1-ed2cc5da591f@pengutronix.de (mailing list archive)
State New
Headers show
Series USB-Serial serdev support | expand

Commit Message

Marco Felsch Aug. 7, 2024, 2:08 p.m. UTC
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(-)

Comments

Jiri Slaby Aug. 8, 2024, 7:51 a.m. UTC | #1
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,
Marco Felsch Aug. 19, 2024, 10:19 a.m. UTC | #2
Hi,

sorry for not replying earlier.

On 24-08-08, Jiri Slaby wrote:
> 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?

Can you please elaborate a bit more? I don't see how the
tty_lookup_driver() is involved in the serdev-ctrl open path anyway.

Regards,
  Marco
Jiri Slaby Aug. 19, 2024, 10:42 a.m. UTC | #3
On 19. 08. 24, 12:19, Marco Felsch wrote:
> Hi,
> 
> sorry for not replying earlier.
> 
> On 24-08-08, Jiri Slaby wrote:
>> 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?
> 
> Can you please elaborate a bit more? I don't see how the
> tty_lookup_driver() is involved in the serdev-ctrl open path anyway.

It's called now in of tty_kopen_exclusive()->tty_kopen(). 
(tty_lookup_driver() is the major difference between the raw 
tty_init_dev() and tty_kopen_exclusive().)
Marco Felsch Aug. 19, 2024, 12:23 p.m. UTC | #4
On 24-08-19, Jiri Slaby wrote:
> On 19. 08. 24, 12:19, Marco Felsch wrote:
> > Hi,
> > 
> > sorry for not replying earlier.
> > 
> > On 24-08-08, Jiri Slaby wrote:
> > > 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?
> > 
> > Can you please elaborate a bit more? I don't see how the
> > tty_lookup_driver() is involved in the serdev-ctrl open path anyway.
> 
> It's called now in of tty_kopen_exclusive()->tty_kopen().
> (tty_lookup_driver() is the major difference between the raw tty_init_dev()
> and tty_kopen_exclusive().)

Okay now I get the "now added tty_lookup_driver()" statement, sorry.
Yes, I believe that this is negligible. The main difference for me was
that the tty_port_set_kopened() is set accordingly which which is
important to not trigger warnings during the release path.

Regards,
  Marco

> 
> -- 
> js
> suse labs
> 
>
Marco Felsch Aug. 21, 2024, 7:25 a.m. UTC | #5
On 24-08-08, Jiri Slaby wrote:
> 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?

Any other comments, suggestions apart this one?

Regards,
  Marco

> 
> thanks,
> -- 
> js
> suse labs
> 
>
diff mbox series

Patch

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);
 	if (IS_ERR(tty))
 		return PTR_ERR(tty);
 	serport->tty = tty;
@@ -144,7 +147,7 @@  static int ttyport_open(struct serdev_controller *ctrl)
 	tty->ops->close(tty, NULL);
 err_unlock:
 	tty_unlock(tty);
-	tty_release_struct(tty, serport->tty_idx);
+	tty_kclose(tty);
 
 	return ret;
 }
@@ -161,7 +164,7 @@  static void ttyport_close(struct serdev_controller *ctrl)
 		tty->ops->close(tty, NULL);
 	tty_unlock(tty);
 
-	tty_release_struct(tty, serport->tty_idx);
+	tty_kclose(tty);
 }
 
 static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed)