[PATCH RESEND 3/3] mm: introduce ARCH_HAS_PTE_DEVMAP

[Anshuman Khandual]

On 04/13/2019 12:31 AM, Robin Murphy wrote:
> ARCH_HAS_ZONE_DEVICE is somewhat meaningless in itself, and combined
> with the long-out-of-date comment can lead to the impression than an
> architecture may just enable it (since __add_pages() now "comprehends
> device memory" for itself) and expect things to work.
> 
> In practice, however, ZONE_DEVICE users have little chance of
> functioning correctly without __HAVE_ARCH_PTE_DEVMAP, so let's clean
> that up the same way as ARCH_HAS_PTE_SPECIAL and make it the proper
> dependency so the real situation is clearer.
> 
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>

Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>