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iio: adc: exynos: do not rely on 'users' counter in ISR 

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@collabora.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://lore.kernel.org/r/20201006215509.GA2556081@dtor-ws
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
dmitry.torokhov@gmail.com 2020-10-06 14:55:09 -07:00 committed by Jonathan Cameron
parent 5b19ca2c78
commit c5bf4d645f
1 changed files with 6 additions and 1 deletions
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7
drivers/iio/adc/exynos_adc.c
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@ -7,6 +7,7 @@
* Copyright (C) 2013 Naveen Krishna Chatradhi <ch.naveen@samsung.com>
*/
#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;
@ -651,7 +654,7 @@ 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;
@ -731,6 +734,7 @@ 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;
@ -740,6 +744,7 @@ 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);
}