[PATCH v4] iio: accel: kxsd9: fix runtime PM leak in write_raw

[Biren Pandya]

The kxsd9 driver previously used manual pm_runtime_get_sync() and
pm_runtime_put_autosuspend() calls around the entire kxsd9_write_raw()
function. If the user provides a non-zero integer component for scale,
the function returned -EINVAL directly, leaking the runtime PM usage
counter.

Move the mask and value validation checks before pm_runtime_get_sync()
to ensure the early -EINVAL returns do not leak the usage counter.

Fixes: 9a9a369d6178 ("iio: accel: kxsd9: Deploy system and runtime PM")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Biren Pandya <birenpandya@xxxxxxxxx>
---
Changes since the reviewed version:
- Reduced to the minimal write_raw() leak fix. Dropped the remove()
  rework (no underflow is possible — pm_runtime_put_noidle() floors at 0)
  and deferred the PM-macro conversion and style cleanup to a follow-up
  series, per Jonathan Cameron and Andy Shevchenko.
 drivers/iio/accel/kxsd9.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/iio/accel/kxsd9.c b/drivers/iio/accel/kxsd9.c
index 4717d80fc24af..1af04cb4bf86a 100644
--- a/drivers/iio/accel/kxsd9.c
+++ b/drivers/iio/accel/kxsd9.c
@@ -139,18 +139,18 @@ static int kxsd9_write_raw(struct iio_dev *indio_dev,
 			   int val2,
 			   long mask)
 {
-	int ret = -EINVAL;
 	struct kxsd9_state *st = iio_priv(indio_dev);
+	int ret;
 
-	pm_runtime_get_sync(st->dev);
+	if (mask != IIO_CHAN_INFO_SCALE)
+		return -EINVAL;
 
-	if (mask == IIO_CHAN_INFO_SCALE) {
-		/* Check no integer component */
-		if (val)
-			return -EINVAL;
-		ret = kxsd9_write_scale(indio_dev, val2);
-	}
+	/* Check no integer component */
+	if (val)
+		return -EINVAL;
 
+	pm_runtime_get_sync(st->dev);
+	ret = kxsd9_write_scale(indio_dev, val2);
 	pm_runtime_put_autosuspend(st->dev);
 
 	return ret;
-- 
2.50.1 (Apple Git-155)