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

Vineet Gupta vgupta at kernel.org
Sun Apr 2 16:52:20 AEST 2023

CC Shahab

On 3/27/23 17:43, Arnd Bergmann wrote:
> From: Arnd Bergmann<arnd at 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 at arndb.de>

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

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


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