Re: [PATCH 13/21] arc: dma-mapping: skip invalidating before bidirectional DMA

Vineet Gupta
2023-04-02T06:52:41Z

CC Shahab

On 3/27/23 17:43, Arnd Bergmann wrote:
> From: Arnd Bergmann<arnd@arndb.de>
>
> Some architectures that need to invalidate buffers after bidirectional
> DMA because of speculative prefetching only do a simpler writeback
> before that DMA, while architectures that don't need to do the second
> invalidate tend to have a combined writeback+invalidate before the
> DMA.
>
> arc is one of the architectures that does both, which seems unnecessary.
>
> Change it to behave like arm/arm64/xtensa instead, and use just a
> writeback before the DMA when we do the invalidate afterwards.
>
> Signed-off-by: Arnd Bergmann<arnd@arndb.de>

Reviewed-by: Vineet Gupta <vgupta@kernel.org>

Shahab can you give this a spin on hsdk - run glibc testsuite over ssh
and make sure nothing strange happens.

Thx,
-Vineet