2022-07-09 04:54:10

by Dmitry Torokhov

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

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 <[email protected]>
---

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

2022-07-18 09:36:08

by Artur Rojek

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

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 <[email protected]>
> ---
>
> 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 <[email protected]>

>
> 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