[PATCH 2/7] libnvdimm/pmem: Honor force_raw for legacy pmem regions

From: Dan Williams
Date: Tue Feb 12 2019 - 16:37:33 EST

For recovery, where non-dax access is needed to a given physical address
range, and testing, allow the 'force_raw' attribute to override the
default establishment of a dev_pagemap.

Otherwise without this capability it is possible to end up with a
namespace that can not be activated due to corrupted info-block, and one
that can not be repaired due to a section collision.

Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 004f1afbe199 ("libnvdimm, pmem: direct map legacy pmem by default")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
drivers/nvdimm/namespace_devs.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index 4b077555ac70..33a3b23b3db7 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -138,6 +138,7 @@ 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_common *ndns = to_ndns(dev);
struct nd_namespace_io *nsio;

@@ -149,6 +150,9 @@ bool pmem_should_map_pages(struct device *dev)
if (is_nd_pfn(dev) || is_nd_btt(dev))
return false;

+ if (ndns->force_raw)
+ return false;
nsio = to_nd_namespace_io(dev);
if (region_intersects(nsio->res.start, resource_size(&nsio->res),