On Mon, Feb 05, 2024 at 04:58:14PM +0100, Nuno Sa via B4 Relay wrote: > From: Nuno Sa <nuno.sa@xxxxxxxxxx> > > Aligning to the L1 cache does 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@xxxxxxxxxx/ > > Fixes: c18e2760308e ("counter: Provide alternative counter registration functions") > Signed-off-by: Nuno Sa <nuno.sa@xxxxxxxxxx> > --- > William, if you prefer, we can do something like in IIO and add a > specific COUNTER_DMA_MINALIGN define > --- > drivers/counter/counter-core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c > index 09c77afb33ca..073bf6b67a57 100644 > --- a/drivers/counter/counter-core.c > +++ b/drivers/counter/counter-core.c > @@ -34,7 +34,7 @@ struct counter_device_allochelper { > * This is cache line aligned to ensure private data behaves like if it > * were kmalloced separately. > */ > - unsigned long privdata[] ____cacheline_aligned; > + unsigned long privdata[] __aligned(ARCH_DMA_MINALIGN); > }; > > static void counter_device_release(struct device *dev) > > --- > base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d > change-id: 20240205-counter-align-fix-3faebfb572af > -- > > Thanks! > - Nuno Sá Hi Nunon, This change sounds reasonable, but should the comment block above privdata be updated to reflect the change? Sincerely, William Breathitt Gray
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