On Tue, 6 Oct 2020 14:55:09 -0700
dmitry.torokhov@xxxxxxxxx wrote:
> The order in which 'users' counter is decremented vs calling drivers'
> close() method is implementation specific, and we should not rely on
> it. Let's introduce driver private flag and use it to signal ISR
> to exit when device is being closed.
>
> This has a side-effect of fixing issue of accessing inut->users
> outside of input->mutex protection.
>
> Reported-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx>
> Acked-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> Reviewed-by: Michał Mirosław <mirq-linux@xxxxxxxxxxxx>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to work their magic.
Given this doesn't have a fixes tag etc I'm assuming it isn't
high priority etc. Let me know if it is!
Thanks,
Jonathan
> ---
>
> v3: fixed typo in exynos_adc_ts_close() per Michał Mirosław
> v2: switched from ordinary read/write to READ_ONCE/WRITE_ONCE per Michał
> Mirosław
>
> drivers/iio/adc/exynos_adc.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
> index 22131a677445..908df4b9b93c 100644
> --- a/drivers/iio/adc/exynos_adc.c
> +++ b/drivers/iio/adc/exynos_adc.c
> @@ -7,6 +7,7 @@
> * Copyright (C) 2013 Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx>
> */
>
> +#include <linux/compiler.h>
> #include <linux/module.h>
> #include <linux/platform_device.h>
> #include <linux/interrupt.h>
> @@ -135,6 +136,8 @@ struct exynos_adc {
> u32 value;
> unsigned int version;
>
> + bool ts_enabled;
> +
> bool read_ts;
> u32 ts_x;
> u32 ts_y;
> @@ -633,7 +636,7 @@ static irqreturn_t exynos_ts_isr(int irq, void *dev_id)
> bool pressed;
> int ret;
>
> - while (info->input->users) {
> + while (READ_ONCE(info->ts_enabled)) {
> ret = exynos_read_s3c64xx_ts(dev, &x, &y);
> if (ret == -ETIMEDOUT)
> break;
> @@ -712,6 +715,7 @@ static int exynos_adc_ts_open(struct input_dev *dev)
> {
> struct exynos_adc *info = input_get_drvdata(dev);
>
> + WRITE_ONCE(info->ts_enabled, true);
> enable_irq(info->tsirq);
>
> return 0;
> @@ -721,6 +725,7 @@ static void exynos_adc_ts_close(struct input_dev *dev)
> {
> struct exynos_adc *info = input_get_drvdata(dev);
>
> + WRITE_ONCE(info->ts_enabled, false);
> disable_irq(info->tsirq);
> }
>
