[PATCH v2 04/25] mm: enhance region_is_ram() to distinguish 'unknown' vs 'mixed'
toshi.kani at hp.com
Tue Jul 28 14:33:11 PDT 2015
On Fri, 2015-07-24 at 22:38 -0400, Dan Williams wrote:
> region_is_ram() is used to prevent the establishment of aliased mappings
> to physical "System RAM" with incompatible cache settings. However, it
> uses "-1" to indicate both "unknown" memory ranges (ranges not described
> by platform firmware) and "mixed" ranges (where the parameters describe
> a range that partially overlaps "System RAM").
> Fix this up by explicitly tracking the "unknown" vs "mixed" resource
> cases. In addition to clarifying that "-1" means the requested spanned
> RAM and non-RAM resource, this re-write also adds support for detecting
> when the requested range completely covers all of a resource.
Agreed - this is a good enhancement.
> Finally, the implementation treats overlaps between "unknown" and RAM as
This sounds right for this interface. iomem_map_sanity_check() checks the
boundary condition with the resource table.
> Cc: Toshi Kani <toshi.kani at hp.com>
> Signed-off-by: Dan Williams <dan.j.williams at intel.com>
The changes look good as well.
Reviewed-by: Toshi Kani <toshi.kani at hp.com>
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