libnvdimm/pmem: Honor force_raw for legacy pmem regions

BugLink: https://bugs.launchpad.net/bugs/1837952
commit fa7d2e639cd90442d868dfc6ca1d4cc9d8bf206e upstream.

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@vger.kernel.org>
Fixes: 004f1afbe199 ("libnvdimm, pmem: direct map legacy pmem by default")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index b8d8b624e8e7040827dd5b09dc8f6626946e546d..eabdf2a6f2957c524f28c748e9fafb5d940f38ff 100644 (file)
--- 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;
 
        if (!IS_ENABLED(CONFIG_ZONE_DEVICE))
@@ -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),
                                IORESOURCE_SYSTEM_RAM,