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

Shahab Vahedi
2023-04-04T08:48:19Z

On 4/2/23 08:52, Vineet Gupta wrote:
> 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

On it.
--
Shahab