This is a note to let you know that I've just added the patch titled
iio: commom: st_sensors: ensure proper DMA alignment
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iio-commom-st_sensors-ensure-proper-dma-alignment.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 862cf85fef85becc55a173387527adb4f076fab0 Mon Sep 17 00:00:00 2001
From: Nuno Sa <nuno.sa@xxxxxxxxxx>
Date: Wed, 31 Jan 2024 10:16:47 +0100
Subject: iio: commom: st_sensors: ensure proper DMA alignment
From: Nuno Sa <nuno.sa@xxxxxxxxxx>
commit 862cf85fef85becc55a173387527adb4f076fab0 upstream.
Aligning the buffer to the L1 cache is not sufficient in some platforms
as they might have larger cacheline sizes for caches after L1 and thus,
we can't guarantee DMA safety.
That was the whole reason to introduce IIO_DMA_MINALIGN in [1]. Do the same
for st_sensors common buffer.
While at it, moved the odr_lock before buffer_data as we definitely
don't want any other data to share a cacheline with the buffer.
[1]: https://lore.kernel.org/linux-iio/20220508175712.647246-2-jic23@xxxxxxxxxx/
Fixes: e031d5f558f1 ("iio:st_sensors: remove buffer allocation at each buffer enable")
Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx>
Cc: <Stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20240131-dev_dma_safety_stm-v2-1-580c07fae51b@xxxxxxxxxx
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/linux/iio/common/st_sensors.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/include/linux/iio/common/st_sensors.h
+++ b/include/linux/iio/common/st_sensors.h
@@ -258,9 +258,9 @@ struct st_sensor_data {
bool hw_irq_trigger;
s64 hw_timestamp;
- char buffer_data[ST_SENSORS_MAX_BUFFER_SIZE] ____cacheline_aligned;
-
struct mutex odr_lock;
+
+ char buffer_data[ST_SENSORS_MAX_BUFFER_SIZE] __aligned(IIO_DMA_MINALIGN);
};
#ifdef CONFIG_IIO_BUFFER
Patches currently in stable-queue which might be from nuno.sa@xxxxxxxxxx are
queue-6.6/iio-imu-adis-ensure-proper-dma-alignment.patch
queue-6.6/iio-adc-ad_sigma_delta-ensure-proper-dma-alignment.patch
queue-6.6/iio-adc-ad4130-zero-initialize-clock-init-data.patch
queue-6.6/iio-commom-st_sensors-ensure-proper-dma-alignment.patch
queue-6.6/iio-adc-ad4130-only-set-gpio_ctrl-if-pin-is-unused.patch
