FAILED: patch "[PATCH] libnvdimm/pmem: Honor force_raw for legacy pmem regions" failed to apply to 4.4-stable tree

The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From fa7d2e639cd90442d868dfc6ca1d4cc9d8bf206e Mon Sep 17 00:00:00 2001
From: Dan Williams <[email protected]>
Date: Thu, 24 Jan 2019 17:33:06 -0800
Subject: [PATCH] libnvdimm/pmem: Honor force_raw for legacy pmem regions

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.

index 4b077555ac70..33a3b23b3db7 100644
@@ -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,