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

[Shahab Vahedi]

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

Tested-by: Shahab Vahedi <shahab at synopsys.com>

No regression was observed for the ARC target before and after applying
these 21 patches. The test environment and its summary follow.

board:  ARC HSDK
base:   repo:   linux-next
        tag:    next-20230403
        commit: 31bd35b66249 Add linux-next specific files for 20230403
hotfix: net: stmmac: check fwnode for phy device before scanning for phy [1]
glibc:  2.37

Summary of test results:
     20 FAIL
   4227 PASS
     38 UNSUPPORTED
     16 XFAIL
      2 XPASS

[1]
https://lore.kernel.org/lkml/20230405093945.3549491-1-michael.wei.hong.sit@intel.com/#r

-- 
Shahab