[PATCH v2 4/4] drivers: dma-coherent: use memset_io for DMA_MEMORY_IO mappings

[Andrew Morton]

On Mon, 29 Feb 2016 16:09:24 +0000 Brian Starkey <brian.starkey at arm.com> wrote:

> Use memset_io() for DMA_MEMORY_IO mappings which are mapped as I/O
> memory, and regular memset() for DMA_MEMORY_MAP mappings.
> 
> This fixes the below alignment fault on arm64 for DMA_MEMORY_IO
> mappings, where memset() uses the DC ZVA instruction which is
> invalid on device memory.

What's the urgency of this fix?  "Hair on fire needed in stable asap"
or "Nice to have in there for 4.6" or what?