[PATCH v2 2/2] treewide: Add the __GFP_PACKED flag to several non-DMA kmalloc() allocations

[Christoph Hellwig]

On Tue, Nov 01, 2022 at 05:32:14PM +0000, Catalin Marinas wrote:
> There's also the case of low-end phones with all RAM below 4GB and arm64
> doesn't allocate the swiotlb. Not sure those vendors would go with a
> recent kernel anyway.
> 
> So the need for swiotlb now changes from 32-bit DMA to any DMA
> (non-coherent but we can't tell upfront when booting, devices may be
> initialised pretty late).

Yes.  The other option would be to use the dma coherent pool for the
bouncing, which must be present on non-coherent systems anyway.  But
it would require us to write a new set of bounce buffering routines.