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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Peter Meerwald <pmeerw@pmeerw.net>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 260/348] iio: accel: bma180: Fix buffer alignment in iio_push_to_buffers_with_timestamp()
Date:   Mon, 12 Jul 2021 08:10:44 +0200
Message-Id: <20210712060737.645169845@linuxfoundation.org>
In-Reply-To: <20210712060659.886176320@linuxfoundation.org>
References: <20210712060659.886176320@linuxfoundation.org>
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From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

[ Upstream commit fc36da3131a747a9367a05caf06de19be1bcc972 ]

To make code more readable, use a structure to express the channel
layout and ensure the timestamp is 8 byte aligned.

Found during an audit of all calls of this function.

Fixes: b9a6a237ffc9 ("iio:bma180: Drop _update_scan_mode()")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-2-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/iio/accel/bma180.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/accel/bma180.c b/drivers/iio/accel/bma180.c
index 1574e4604a4f..aa301c606346 100644
--- a/drivers/iio/accel/bma180.c
+++ b/drivers/iio/accel/bma180.c
@@ -119,7 +119,11 @@ struct bma180_data {
 	int scale;
 	int bw;
 	bool pmode;
-	u8 buff[16]; /* 3x 16-bit + 8-bit + padding + timestamp */
+	/* Ensure timestamp is naturally aligned */
+	struct {
+		s16 chan[4];
+		s64 timestamp __aligned(8);
+	} scan;
 };
 
 enum bma180_chan {
@@ -675,12 +679,12 @@ static irqreturn_t bma180_trigger_handler(int irq, void *p)
 			mutex_unlock(&data->mutex);
 			goto err;
 		}
-		((s16 *)data->buff)[i++] = ret;
+		data->scan.chan[i++] = ret;
 	}
 
 	mutex_unlock(&data->mutex);
 
-	iio_push_to_buffers_with_timestamp(indio_dev, data->buff, time_ns);
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan, time_ns);
 err:
 	iio_trigger_notify_done(indio_dev->trig);
 
-- 
2.30.2