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| author | Nuno Sa <nuno.sa@analog.com> | 2024-02-09 16:50:34 +0100 |
|---|---|---|
| committer | William Breathitt Gray <wbg@ishicorp.com> | 2024-02-16 18:51:00 -0500 |
| commit | c83ccdc9586b3e9882da9e27507c046751999d59 (patch) | |
| tree | b55ded02769aef6d1bfee67c39e24f863293ae32 /drivers/counter | |
| parent | 6613476e225e090cc9aad49be7fa504e290dd33d (diff) | |
| download | linux-c83ccdc9586b3e9882da9e27507c046751999d59.tar.gz | |
counter: fix privdata alignment
Aligning to the L1 cache does not guarantee the same alignment as
kmallocing an object [1]. Furthermore, in some platforms, that
alignment is not sufficient for DMA safety (in case someone wants
to have a DMA safe buffer in privdata) [2].
Sometime ago, we had the same fixes in IIO.
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/base/devres.c#n35
[2]: https://lore.kernel.org/linux-iio/20220508175712.647246-2-jic23@kernel.org/
Fixes: c18e2760308e ("counter: Provide alternative counter registration functions")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240209-counter-align-fix-v2-1-5777ea0a2722@analog.com
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Diffstat (limited to 'drivers/counter')
| -rw-r--r-- | drivers/counter/counter-core.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c index 09c77afb33ca84..3f24481fc04a12 100644 --- a/drivers/counter/counter-core.c +++ b/drivers/counter/counter-core.c @@ -31,10 +31,11 @@ struct counter_device_allochelper { struct counter_device counter; /* - * This is cache line aligned to ensure private data behaves like if it - * were kmalloced separately. + * This ensures private data behaves like if it were kmalloced + * separately. Also ensures the minimum alignment for safe DMA + * operations (which may or may not mean cache alignment). */ - unsigned long privdata[] ____cacheline_aligned; + unsigned long privdata[] __aligned(ARCH_DMA_MINALIGN); }; static void counter_device_release(struct device *dev) |