On Fri, Jun 05, 2020 at 07:33:33PM +0200, Andrzej Pietrasiewicz wrote:
> A new helper is available, so use it. Inspecting 'users' member of
> input_dev requires taking device's mutex.
> 
> Signed-off-by: Andrzej Pietrasiewicz <andrze...@collabora.com>
> ---
>  drivers/iio/adc/exynos_adc.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
> index 22131a677445..294715bafe25 100644
> --- a/drivers/iio/adc/exynos_adc.c
> +++ b/drivers/iio/adc/exynos_adc.c
> @@ -630,10 +630,13 @@ static irqreturn_t exynos_ts_isr(int irq, void *dev_id)
>       struct exynos_adc *info = dev_id;
>       struct iio_dev *dev = dev_get_drvdata(info->dev);
>       u32 x, y;
> -     bool pressed;
> +     bool pressed, cont;
>       int ret;
>  
> -     while (info->input->users) {
> +     mutex_lock(&info->input->mutex);
> +     cont = input_device_enabled(info->input);
> +     mutex_unlock(&info->input->mutex);
> +     while (cont) {
>               ret = exynos_read_s3c64xx_ts(dev, &x, &y);
>               if (ret == -ETIMEDOUT)
>                       break;
> @@ -651,6 +654,10 @@ static irqreturn_t exynos_ts_isr(int irq, void *dev_id)
>               input_sync(info->input);
>  
>               usleep_range(1000, 1100);
> +
> +             mutex_lock(&info->input->mutex);
> +             cont = input_device_enabled(info->input);
> +             mutex_unlock(&info->input->mutex);
>       }

The mutex doesn't really protect anything here, but I would nevertheless
suggest this sequence instead:

lock()
while (test) {
        unlock()
        ...
        lock()
}
unlock()

Best Regards,
Michał Mirosław

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