[PATCH 5.19 0673/1157] iio: dac: ad5360: Fix alignment for DMA safety

Greg Kroah-Hartman
2022-08-16T04:35:30Z

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

[ Upstream commit 94ec314e1bd686b669c24385ce2dbc967eb74147 ]

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1. Switch to the updated
IIO_DMA_MINALIGN definition.

Update the comment to include 'may'.

Fixes: a3e2940c24d3 ("staging:iio:dac: Add AD5360 driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-45-jic23@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iio/dac/ad5360.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/dac/ad5360.c b/drivers/iio/dac/ad5360.c
index 22b000a40828..e0b7f658d611 100644
--- a/drivers/iio/dac/ad5360.c
+++ b/drivers/iio/dac/ad5360.c
@@ -79,13 +79,13 @@ struct ad5360_state {
struct mutex lock;

/*
- * DMA (thus cache coherency maintenance) requires the
+ * DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
*/
union {
__be32 d32;
u8 d8[4];
- } data[2] ____cacheline_aligned;
+ } data[2] __aligned(IIO_DMA_MINALIGN);
};

enum ad5360_type {
--
2.35.1