Re: [PATCH 6/7] dma-direct: handle DMA_ATTR_NO_KERNEL_MAPPING in common code

[Guenter Roeck]

On Fri, Jun 14, 2019 at 04:44:30PM +0200, Christoph Hellwig wrote:
> DMA_ATTR_NO_KERNEL_MAPPING is generally implemented by allocating
> normal cacheable pages or CMA memory, and then returning the page
> pointer as the opaque handle.  Lift that code from the xtensa and
> generic dma remapping implementations into the generic dma-direct
> code so that we don't even call arch_dma_alloc for these allocations.
> 
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>

This patch results in build failures for mips:nlm_xlp_defconfig and
mips:cavium_octeon_defconfig.

kernel/dma/direct.c:144: undefined reference to `arch_dma_prep_coherent'

Reverting the patch fixes the problem.

Guenter