From 7e6f8cbc5e10cf7601c762db267b795273d53078 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Date: Wed, 8 Jan 2020 12:16:47 +0530
Subject: [PATCH] powerpc/papr_scm: Don't enable direct map for a region by
 default

References: bsc#1129551
Patch-mainline: v5.6-rc1
Git-commit: 7e6f8cbc5e10cf7601c762db267b795273d53078

Setting ND_REGION_PAGEMAP flag implies namespace mode defaults to fsdax mode.
This also means kernel ends up creating struct page backing for these namspace
ranges. With large namespaces that is not the right thing to do. We
should let the user select the mode he/she wants the namespace to be created
with.

Hence disable ND_REGION_PAGEMAP for papr_scm regions. We still keep the flag for
of_pmem because it supports only small persistent memory regions.

This is similar to what is done for x86 with commit
commit: 004f1afbe199 ("libnvdimm, pmem: direct map legacy pmem by default")

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200108064647.169637-1-aneesh.kumar@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/platforms/pseries/papr_scm.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index cdd316c6cef3..8da39a9c5569 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -357,7 +357,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	ndr_desc.mapping = &mapping;
 	ndr_desc.num_mappings = 1;
 	ndr_desc.nd_set = &p->nd_set;
-	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
 
 	if (p->is_volatile)
 		p->region = nvdimm_volatile_region_create(p->bus, &ndr_desc);
-- 
2.23.0