[PATCH 14/25] iio:pressure:ms5611 Fix buffer element alignment

[Jonathan Cameron <jic23@kernel.org>]

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

One of a class of bugs pointed out by Lars in a recent review.
iio_push_to_buffers_with_timestamp assumes the buffer used is aligned
to the size of the timestamp (8 bytes).  This is not guaranteed in
this driver which uses an array of smaller elements on the stack.
Here there is no data leak possibility so use an explicit structure
on the stack to ensure alignment and nice readable fashion.

Fixes: 713bbb4efb9dc ("iio: pressure: ms5611: Add triggered buffer support")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/iio/pressure/ms5611_core.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/pressure/ms5611_core.c b/drivers/iio/pressure/ms5611_core.c
index 2f598ad91621..ba9cf9d77a4a 100644
--- a/drivers/iio/pressure/ms5611_core.c
+++ b/drivers/iio/pressure/ms5611_core.c
@@ -212,16 +212,21 @@ static irqreturn_t ms5611_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct ms5611_state *st = iio_priv(indio_dev);
-	s32 buf[4]; /* s32 (pressure) + s32 (temp) + 2 * s32 (timestamp) */
+	/* Ensure buffer elements are naturally aligned */
+	struct {
+		s32 channels[2];
+		s64 ts;
+	} scan;
 	int ret;
 
 	mutex_lock(&st->lock);
-	ret = ms5611_read_temp_and_pressure(indio_dev, &buf[1], &buf[0]);
+	ret = ms5611_read_temp_and_pressure(indio_dev, &scan.channels[1],
+					    &scan.channels[0]);
 	mutex_unlock(&st->lock);
 	if (ret < 0)
 		goto err;
 
-	iio_push_to_buffers_with_timestamp(indio_dev, buf,
+	iio_push_to_buffers_with_timestamp(indio_dev, &scan,
 					   iio_get_time_ns(indio_dev));
 
 err:
-- 
2.26.2