RE: [PATCH] dma: Per-NUMA-node CMA should depend on NUMA

[Song Bao Hua (Barry Song)]

> -----Original Message-----
> From: Robin Murphy [mailto:robin.murphy@xxxxxxx]
> Sent: Tuesday, October 27, 2020 1:25 AM
> To: hch@xxxxxx
> Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Song Bao
> Hua (Barry Song) <song.bao.hua@xxxxxxxxxxxxx>
> Subject: [PATCH] dma: Per-NUMA-node CMA should depend on NUMA
> 
> Offering DMA_PERNUMA_CMA to non-NUMA configs is pointless.
> 

This is right.

> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
> ---
>  kernel/dma/Kconfig | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
> index c99de4a21458..964b74c9b7e3 100644
> --- a/kernel/dma/Kconfig
> +++ b/kernel/dma/Kconfig
> @@ -125,7 +125,8 @@ if  DMA_CMA
> 
>  config DMA_PERNUMA_CMA
>  	bool "Enable separate DMA Contiguous Memory Area for each NUMA
> Node"
> -	default NUMA && ARM64
> +	depends on NUMA
> +	default ARM64

On the other hand, at this moment, only ARM64 is calling the init code
to get per_numa cma. Do we need to
depends on NUMA && ARM64 ?
so that this is not enabled by non-arm64?

>  	help
>  	  Enable this option to get pernuma CMA areas so that devices like
>  	  ARM64 SMMU can get local memory by DMA coherent APIs.
> --
 
Thanks
Barry