6.1-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nikhil Gautam <redacted>
[ Upstream commit 579c049b4cb6fc72ce2c505fc5334540be0efcd3 ]
The IIO core does not filter duplicate writes to the event enable
attribute, so writing the same value twice invokes
write_event_config() twice. Enabling twice leaks a runtime PM
reference, preventing the device from ever suspending again;
disabling twice underflows the usage count and triggers a
"Runtime PM usage count underflow" warning.
Bail out early when the requested state matches the current state.
While at it, switch to pm_runtime_resume_and_get() so a failed
resume is propagated to userspace instead of silently marking the
event enabled.
Fixes: 97d642e23037c ("iio: light: Add a driver for Sharp GP2AP002x00F")
Signed-off-by: Nikhil Gautam <redacted>
Signed-off-by: Jonathan Cameron <redacted>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/light/gp2ap002.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/iio/light/gp2ap002.c b/drivers/iio/light/gp2ap002.c
index 45c3128ec2fc8..dca2ddd9a7639 100644
--- a/drivers/iio/light/gp2ap002.c
+++ b/drivers/iio/light/gp2ap002.c
@@ -343,6 +343,10 @@ static int gp2ap002_write_event_config(struct iio_dev *indio_dev,
int state)
{
struct gp2ap002 *gp2ap002 = iio_priv(indio_dev);
+ int ret;
+
+ if (state == gp2ap002->enabled)
+ return 0;
if (state) {
/*@@ -350,14 +354,17 @@ static int gp2ap002_write_event_config(struct iio_dev *indio_dev,
* already) and reintialize the sensor by using runtime_pm
* callbacks.
*/
- pm_runtime_get_sync(gp2ap002->dev);
- gp2ap002->enabled = true;
+ ret = pm_runtime_resume_and_get(gp2ap002->dev);
+ if (ret)
+ return ret;
+
} else {
pm_runtime_mark_last_busy(gp2ap002->dev);
pm_runtime_put_autosuspend(gp2ap002->dev);
- gp2ap002->enabled = false;
}
+ gp2ap002->enabled = state;
+
return 0;
}
--
2.53.0