On Wed, Jan 10, 2018 at 12:58:14PM +0000, Robin Murphy wrote: > On 10/01/18 08:09, Christoph Hellwig wrote: >> arm64 uses ZONE_DMA for allocations below 32-bits. These days we >> name the zone for that ZONE_DMA32, which will allow to use the >> dma-direct and generic swiotlb code as-is, so rename it. > > I do wonder if we could also "upgrade" GFP_DMA to GFP_DMA32 somehow when > !ZONE_DMA - there are almost certainly arm64 drivers out there using a > combination of GFP_DMA and streaming mappings which will no longer get the > guaranteed 32-bit addresses they expect after this. I'm not sure quite how > feasible that is, though :/ I can't find anything obvious in the tree. The alternative would be to keep ZONE_DMA and set ARCH_ZONE_DMA_BITS. > That said, I do agree that this is an appropriate change (the legacy of > GFP_DMA is obviously horrible), so, provided we get plenty of time to find > and fix the fallout when it lands: > > Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx> I was hoping to get this into 4.15. What would be proper time to fix the fallout?
