media: input: Convert timers to use timer_setup()

  In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

One input_dev user hijacks the input_dev software autorepeat timer to
perform its own repeat management. However, there is no path back to the
existing status variable, so add a generic one to the input structure and
use that instead.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Geliang Tang <geliangtang@gmail.com>
Cc: linux-input@vger.kernel.org
Cc: linux-media@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Pali Rohár <pali.rohar@gmail.com>
---
 drivers/input/input.c               | 12 ++++++------
 drivers/media/pci/ttpci/av7110.h    |  1 -
 drivers/media/pci/ttpci/av7110_ir.c | 16 ++++++++--------
 include/linux/input.h               |  2 ++
 4 files changed, 16 insertions(+), 15 deletions(-)
  

On Mon, Oct 16, 2017 at 04:14:43PM -0700, Kees Cook wrote:
> In preparation for unconditionally passing the struct timer_list pointer to
> all timer callbacks, switch to using the new timer_setup() and from_timer()
> to pass the timer pointer explicitly.
> 
> One input_dev user hijacks the input_dev software autorepeat timer to
> perform its own repeat management. However, there is no path back to the
> existing status variable, so add a generic one to the input structure and
> use that instead.

That is too bad and it should not be doing this. I'd rather av7110 used
its own private timer for that.

> 
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
> Cc: Hans Verkuil <hans.verkuil@cisco.com>
> Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
> Cc: Geliang Tang <geliangtang@gmail.com>
> Cc: linux-input@vger.kernel.org
> Cc: linux-media@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Acked-by: Pali Rohár <pali.rohar@gmail.com>
> ---
>  drivers/input/input.c               | 12 ++++++------
>  drivers/media/pci/ttpci/av7110.h    |  1 -
>  drivers/media/pci/ttpci/av7110_ir.c | 16 ++++++++--------
>  include/linux/input.h               |  2 ++
>  4 files changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/input/input.c b/drivers/input/input.c
> index d268fdc23c64..497ad2dcb699 100644
> --- a/drivers/input/input.c
> +++ b/drivers/input/input.c
> @@ -76,7 +76,7 @@ static void input_start_autorepeat(struct input_dev *dev, int code)
>  {
>  	if (test_bit(EV_REP, dev->evbit) &&
>  	    dev->rep[REP_PERIOD] && dev->rep[REP_DELAY] &&
> -	    dev->timer.data) {
> +	    dev->timer.function) {
>  		dev->repeat_key = code;
>  		mod_timer(&dev->timer,
>  			  jiffies + msecs_to_jiffies(dev->rep[REP_DELAY]));
> @@ -179,9 +179,9 @@ static void input_pass_event(struct input_dev *dev,
>   * dev->event_lock here to avoid racing with input_event
>   * which may cause keys get "stuck".
>   */
> -static void input_repeat_key(unsigned long data)
> +static void input_repeat_key(struct timer_list *t)
>  {
> -	struct input_dev *dev = (void *) data;
> +	struct input_dev *dev = from_timer(dev, t, timer);
>  	unsigned long flags;
>  
>  	spin_lock_irqsave(&dev->event_lock, flags);
> @@ -1790,7 +1790,7 @@ struct input_dev *input_allocate_device(void)
>  		device_initialize(&dev->dev);
>  		mutex_init(&dev->mutex);
>  		spin_lock_init(&dev->event_lock);
> -		init_timer(&dev->timer);
> +		timer_setup(&dev->timer, NULL, 0);
>  		INIT_LIST_HEAD(&dev->h_list);
>  		INIT_LIST_HEAD(&dev->node);
>  
> @@ -2053,8 +2053,8 @@ static void devm_input_device_unregister(struct device *dev, void *res)
>   */
>  void input_enable_softrepeat(struct input_dev *dev, int delay, int period)
>  {
> -	dev->timer.data = (unsigned long) dev;
> -	dev->timer.function = input_repeat_key;
> +	dev->timer.function = (TIMER_FUNC_TYPE)input_repeat_key;
> +	dev->timer_data = 0;
>  	dev->rep[REP_DELAY] = delay;
>  	dev->rep[REP_PERIOD] = period;
>  }
> diff --git a/drivers/media/pci/ttpci/av7110.h b/drivers/media/pci/ttpci/av7110.h
> index 347827925c14..b98a4f3006df 100644
> --- a/drivers/media/pci/ttpci/av7110.h
> +++ b/drivers/media/pci/ttpci/av7110.h
> @@ -93,7 +93,6 @@ struct infrared {
>  	u8			inversion;
>  	u16			last_key;
>  	u16			last_toggle;
> -	u8			delay_timer_finished;
>  };
>  
>  
> diff --git a/drivers/media/pci/ttpci/av7110_ir.c b/drivers/media/pci/ttpci/av7110_ir.c
> index ca05198de2c2..a883caa6488c 100644
> --- a/drivers/media/pci/ttpci/av7110_ir.c
> +++ b/drivers/media/pci/ttpci/av7110_ir.c
> @@ -155,16 +155,16 @@ static void av7110_emit_key(unsigned long parm)
>  	if (timer_pending(&ir->keyup_timer)) {
>  		del_timer(&ir->keyup_timer);
>  		if (ir->last_key != keycode || toggle != ir->last_toggle) {
> -			ir->delay_timer_finished = 0;
> +			ir->input_dev->timer_data = 0;
>  			input_event(ir->input_dev, EV_KEY, ir->last_key, 0);
>  			input_event(ir->input_dev, EV_KEY, keycode, 1);
>  			input_sync(ir->input_dev);
> -		} else if (ir->delay_timer_finished) {
> +		} else if (ir->input_dev->timer_data) {
>  			input_event(ir->input_dev, EV_KEY, keycode, 2);
>  			input_sync(ir->input_dev);
>  		}
>  	} else {
> -		ir->delay_timer_finished = 0;
> +		ir->input_dev->timer_data = 0;
>  		input_event(ir->input_dev, EV_KEY, keycode, 1);
>  		input_sync(ir->input_dev);
>  	}
> @@ -206,11 +206,12 @@ static void input_register_keys(struct infrared *ir)
>  
>  
>  /* called by the input driver after rep[REP_DELAY] ms */
> -static void input_repeat_key(unsigned long parm)
> +static void input_repeat_key(struct timer_list *t)
>  {
> -	struct infrared *ir = (struct infrared *) parm;
> +	struct input_dev *dev = from_timer(dev, t, timer);
>  
> -	ir->delay_timer_finished = 1;
> +	/* Key repeat started */
> +	dev->timer_data = 1;
>  }
>  
>  
> @@ -365,8 +366,7 @@ int av7110_ir_init(struct av7110 *av7110)
>  		input_free_device(input_dev);
>  		return err;
>  	}
> -	input_dev->timer.function = input_repeat_key;
> -	input_dev->timer.data = (unsigned long) &av7110->ir;
> +	input_dev->timer.function = (TIMER_FUNC_TYPE)input_repeat_key;
>  
>  	if (av_cnt == 1) {
>  		e = proc_create("av7110_ir", S_IWUSR, NULL, &av7110_ir_proc_fops);
> diff --git a/include/linux/input.h b/include/linux/input.h
> index fb5e23c7ed98..dcd117bf1027 100644
> --- a/include/linux/input.h
> +++ b/include/linux/input.h
> @@ -70,6 +70,7 @@ struct input_value {
>   * @repeat_key: stores key code of the last key pressed; used to implement
>   *	software autorepeat
>   * @timer: timer for software autorepeat
> + * @timer_data: timer data for software autorepeat overrides
>   * @rep: current values for autorepeat parameters (delay, rate)
>   * @mt: pointer to multitouch state
>   * @absinfo: array of &struct input_absinfo elements holding information
> @@ -152,6 +153,7 @@ struct input_dev {
>  
>  	unsigned int repeat_key;
>  	struct timer_list timer;
> +	unsigned long timer_data;
>  
>  	int rep[REP_CNT];
>  
> -- 
> 2.7.4
> 
> 
> -- 
> Kees Cook
> Pixel Security
  

On Thu, Oct 19, 2017 at 3:32 PM, Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
> On Mon, Oct 16, 2017 at 04:14:43PM -0700, Kees Cook wrote:
>> In preparation for unconditionally passing the struct timer_list pointer to
>> all timer callbacks, switch to using the new timer_setup() and from_timer()
>> to pass the timer pointer explicitly.
>>
>> One input_dev user hijacks the input_dev software autorepeat timer to
>> perform its own repeat management. However, there is no path back to the
>> existing status variable, so add a generic one to the input structure and
>> use that instead.
>
> That is too bad and it should not be doing this. I'd rather av7110 used
> its own private timer for that.

Yeah, that was a pretty weird case. I couldn't see how to avoid it,
though. I didn't see a way to hook the autorepeat, but I'm not too
familiar with the code here.

(I am finding such bizarre stuff with this refactoring...)

-Kees
  

On Thu, Oct 19, 2017 at 03:45:38PM -0700, Kees Cook wrote:
> On Thu, Oct 19, 2017 at 3:32 PM, Dmitry Torokhov
> <dmitry.torokhov@gmail.com> wrote:
> > On Mon, Oct 16, 2017 at 04:14:43PM -0700, Kees Cook wrote:
> >> In preparation for unconditionally passing the struct timer_list pointer to
> >> all timer callbacks, switch to using the new timer_setup() and from_timer()
> >> to pass the timer pointer explicitly.
> >>
> >> One input_dev user hijacks the input_dev software autorepeat timer to
> >> perform its own repeat management. However, there is no path back to the
> >> existing status variable, so add a generic one to the input structure and
> >> use that instead.
> >
> > That is too bad and it should not be doing this. I'd rather av7110 used
> > its own private timer for that.
> 
> Yeah, that was a pretty weird case. I couldn't see how to avoid it,
> though. I didn't see a way to hook the autorepeat, but I'm not too
> familiar with the code here.

You just need to manage the private timer in the driver and not mess up
with the input core if input core's autorepeat does not provide the
desired behavior...

Thanks.
  

On Thu, Oct 19, 2017 at 3:48 PM, Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
> On Thu, Oct 19, 2017 at 03:45:38PM -0700, Kees Cook wrote:
>> On Thu, Oct 19, 2017 at 3:32 PM, Dmitry Torokhov
>> <dmitry.torokhov@gmail.com> wrote:
>> > On Mon, Oct 16, 2017 at 04:14:43PM -0700, Kees Cook wrote:
>> >> In preparation for unconditionally passing the struct timer_list pointer to
>> >> all timer callbacks, switch to using the new timer_setup() and from_timer()
>> >> to pass the timer pointer explicitly.
>> >>
>> >> One input_dev user hijacks the input_dev software autorepeat timer to
>> >> perform its own repeat management. However, there is no path back to the
>> >> existing status variable, so add a generic one to the input structure and
>> >> use that instead.
>> >
>> > That is too bad and it should not be doing this. I'd rather av7110 used
>> > its own private timer for that.
>>
>> Yeah, that was a pretty weird case. I couldn't see how to avoid it,
>> though. I didn't see a way to hook the autorepeat, but I'm not too
>> familiar with the code here.
>
> You just need to manage the private timer in the driver and not mess up
> with the input core if input core's autorepeat does not provide the
> desired behavior...

I don't know how to fix this, but I still need to do this refactoring.
What's the correct step forward here? Should I temporarily disable the
timer in av7110?

Seems like the hijacking was introduced in ee820a648fb3 ("V4L/DVB
(5334): Dvb-ttpci: Infrared remote control refactoring").

Thanks!

-Kees