linux-kernel - [PATCH 2/7] libnvdimm/pmem: Honor force

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Message-ID: <155000669130.348031.13764885263577554365.stgit@dwillia2-desk3.amr.corp.intel.com>
Date:   Tue, 12 Feb 2019 13:24:51 -0800
From:   Dan Williams <dan.j.williams@...el.com>
To:     linux-nvdimm@...ts.01.org
Cc:     stable@...r.kernel.org, linux-kernel@...r.kernel.org,
        vishal.l.verma@...el.com, linux-fsdevel@...r.kernel.org
Subject: [PATCH 2/7] 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.

Cc: <stable@...r.kernel.org>
Fixes: 004f1afbe199 ("libnvdimm, pmem: direct map legacy pmem by default")
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
---
 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;
 
 	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,