[PATCH 4.19 180/421] iio: prox: as3935: Fix buffer alignment in iio_push_to_buffers_with_timestamp()

Greg Kroah-Hartman
2021-07-19T16:26:46Z

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

[ Upstream commit 37eb8d8c64f2ecb3a5521ba1cc1fad973adfae41 ]

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 uses of
iio_push_to_buffers_with_timestamp()

Fixes: 37b1ba2c68cf ("iio: proximity: as3935: fix buffer stack trashing")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Matt Ranostay <matt.ranostay@konsulko.com>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-15-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/proximity/as3935.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/iio/proximity/as3935.c b/drivers/iio/proximity/as3935.c
index f130388a16a0..9069eec46093 100644
--- a/drivers/iio/proximity/as3935.c
+++ b/drivers/iio/proximity/as3935.c
@@ -61,7 +61,11 @@ struct as3935_state {
unsigned long noise_tripped;
u32 tune_cap;
u32 nflwdth_reg;
- u8 buffer[16]; /* 8-bit data + 56-bit padding + 64-bit timestamp */
+ /* Ensure timestamp is naturally aligned */
+ struct {
+ u8 chan;
+ s64 timestamp __aligned(8);
+ } scan;
u8 buf[2] ____cacheline_aligned;
};

@@ -227,8 +231,8 @@ static irqreturn_t as3935_trigger_handler(int irq, void *private)
if (ret)
goto err_read;

- st->buffer[0] = val & AS3935_DATA_MASK;
- iio_push_to_buffers_with_timestamp(indio_dev, &st->buffer,
+ st->scan.chan = val & AS3935_DATA_MASK;
+ iio_push_to_buffers_with_timestamp(indio_dev, &st->scan,
iio_get_time_ns(indio_dev));
err_read:
iio_trigger_notify_done(indio_dev->trig);
--
2.30.2