[PATCH] Input: adc-joystick - fix ordering in adc_joystick_probe()

[PATCH] Input: adc-joystick - fix ordering in adc_joystick_probe()

[Dmitry Torokhov]

We should register the IIO buffer before we register the input device,
because as soon as the device is registered input handlers may attach to
it, resulting in a call to adc_joystick_open() which makes use of the said
buffer.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---

Not tested on hardware...

 drivers/input/joystick/adc-joystick.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/input/joystick/adc-joystick.c b/drivers/input/joystick/adc-joystick.c
index 78ebca7d400a..e0cfdc84763f 100644
--- a/drivers/input/joystick/adc-joystick.c
+++ b/drivers/input/joystick/adc-joystick.c
@@ -222,13 +222,6 @@ static int adc_joystick_probe(struct platform_device *pdev)
 	if (error)
 		return error;
 
-	input_set_drvdata(input, joy);
-	error = input_register_device(input);
-	if (error) {
-		dev_err(dev, "Unable to register input device\n");
-		return error;
-	}
-
 	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);
 	if (IS_ERR(joy->buffer)) {
 		dev_err(dev, "Unable to allocate callback buffer\n");
@@ -241,6 +234,14 @@ static int adc_joystick_probe(struct platform_device *pdev)
 		return error;
 	}
 
+	input_set_drvdata(input, joy);
+
+	error = input_register_device(input);
+	if (error) {
+		dev_err(dev, "Unable to register input device\n");
+		return error;
+	}
+
 	return 0;
 }
 
-- 
2.37.0.144.g8ac04bfd2-goog


-- 
Dmitry

Re: [PATCH] Input: adc-joystick - fix ordering in adc_joystick_probe()

[Artur Rojek]

On 2022-07-09 06:35, Dmitry Torokhov wrote:
> We should register the IIO buffer before we register the input device,
> because as soon as the device is registered input handlers may attach 
> to
> it, resulting in a call to adc_joystick_open() which makes use of the 
> said
> buffer.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
> 
> Not tested on hardware...
Hi Dmitry,

nice catch, thanks! I will verify the operation on hardware some time 
over the weekend.
Small nitpick inline. With that changed:

Acked-by: Artur Rojek <contact@artur-rojek.eu>

> 
>  drivers/input/joystick/adc-joystick.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/input/joystick/adc-joystick.c
> b/drivers/input/joystick/adc-joystick.c
> index 78ebca7d400a..e0cfdc84763f 100644
> --- a/drivers/input/joystick/adc-joystick.c
> +++ b/drivers/input/joystick/adc-joystick.c
> @@ -222,13 +222,6 @@ static int adc_joystick_probe(struct 
> platform_device *pdev)
>  	if (error)
>  		return error;
> 
> -	input_set_drvdata(input, joy);
> -	error = input_register_device(input);
> -	if (error) {
> -		dev_err(dev, "Unable to register input device\n");
> -		return error;
> -	}
> -
>  	joy->buffer = iio_channel_get_all_cb(dev, adc_joystick_handle, joy);
>  	if (IS_ERR(joy->buffer)) {
>  		dev_err(dev, "Unable to allocate callback buffer\n");
> @@ -241,6 +234,14 @@ static int adc_joystick_probe(struct 
> platform_device *pdev)
>  		return error;
>  	}
> 
> +	input_set_drvdata(input, joy);
> +
> +	error = input_register_device(input);
> +	if (error) {
> +		dev_err(dev, "Unable to register input device\n");
> +		return error;
> +	}
> +
>  	return 0;
Since this is now the last thing the function does, we can simplify the 
code a bit:
```
	error = input_register_device(input);
	if (error)
		dev_err(dev, "Unable to register input device\n");

	return error;
```

Cheers,
Artur
>  }
> 
> --
> 2.37.0.144.g8ac04bfd2-goog