libnvdimm, pmem: adjust for section collisions with 'System RAM'

On a platform where 'Persistent Memory' and 'System RAM' are mixed
within a given sparsemem section, trim the namespace and notify about the
sub-optimal alignment.

Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 9edf7eb7d17c..f5cb88601359 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -133,6 +133,7 @@ bool nd_is_uuid_unique(struct device *dev, u8 *uuid)
 bool pmem_should_map_pages(struct device *dev)
 {
         struct nd_region *nd_region = to_nd_region(dev->parent);
+        struct nd_namespace_io *nsio;
 
         if (!IS_ENABLED(CONFIG_ZONE_DEVICE))
                 return false;
@@ -143,6 +144,12 @@ bool pmem_should_map_pages(struct device *dev)
         if (is_nd_pfn(dev) || is_nd_btt(dev))
                 return false;
 
+        nsio = to_nd_namespace_io(dev);
+        if (region_intersects(nsio->res.start, resource_size(&nsio->res),
+                                IORESOURCE_SYSTEM_RAM,
+                                IORES_DESC_NONE) == REGION_MIXED)
+                return false;
+
 #ifdef ARCH_MEMREMAP_PMEM
         return ARCH_MEMREMAP_PMEM == MEMREMAP_WB;
 #else