Re: [PATCH 04/20] arm-nommu: use generic dma_noncoherent_ops

[John Garry <john.garry@huawei.com>]

On 11/05/2018 08:59, Christoph Hellwig wrote:
> Switch to the generic noncoherent direct mapping implementation for
> the nommu dma map implementation.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/arc/Kconfig                |   1 +
>  arch/arm/Kconfig                |   4 +
>  arch/arm/mm/dma-mapping-nommu.c | 139 +++++---------------------------
>  3 files changed, 23 insertions(+), 121 deletions(-)
>
> diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
> index 89d47eac18b2..3a492a9aeaad 100644
> --- a/arch/arc/Kconfig
> +++ b/arch/arc/Kconfig
> @@ -9,6 +9,7 @@
>  config ARC
>  	def_bool y
>  	select ARC_TIMERS
> +	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
>  	select ARCH_HAS_SYNC_DMA_FOR_CPU
>  	select ARCH_HAS_SYNC_DMA_FOR_DEVICE

I guess that this arc change is here by accident, no? And isn't 
ARCH_HAS_SYNC_DMA_FOR_DEVICE already selected (by 3/20)?

>  	select ARCH_HAS_SG_CHAIN
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index c43f5bb55ac8..76ddd0064f87 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig