Re: [PATCH 07/21] dma-iommu: move the arm64 wrappers to common code

[Christoph Hellwig]

On Tue, Apr 09, 2019 at 04:07:02PM +0100, Robin Murphy wrote:
>> -static inline int iommu_dma_init(void)
>> +static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base,
>> +		u64 size, const struct iommu_ops *ops)
>>   {
>> -	return 0;
>>   }
>
> I don't think it makes sense to have a stub for that - AFAICS it should 
> only ever be called form arch code with an inherent "select IOMMU_DMA" 
> (much like the stuff which isn't stubbed currently).
>
> Otherwise, I'm about 97% sure the rest of the move looks OK - thanks for 
> splitting things up.

arm64 only selects IOMMU_DMA if IOMMU_SUPPORT is selected, which can
be disabled.  So to keep some (unusual) arm64 configs compiling we'll need
the stub..