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From c8eebc4a99f15280654f23e914e746c40a516e50 Mon Sep 17 00:00:00 2001
From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Date: Fri, 16 Jun 2023 16:38:15 +0530
Subject: [PATCH] powerpc/mm/dax: Fix the condition when checking if altmap
 vmemap can cross-boundary

References: bsc#1150305 ltc#176097 git-fixes
Patch-mainline: v6.5-rc1
Git-commit: c8eebc4a99f15280654f23e914e746c40a516e50

Without this fix, the last subsection vmemmap can end up in memory even if
the namespace is created with -M mem and has sufficient space in the altmap
area.

Fixes: cf387d9644d8 ("libnvdimm/altmap: Track namespace boundaries in altmap")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Tested-by: Sachin Sant <sachinp@linux.ibm.com <mailto:sachinp@linux.ibm.com>>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230616110826.344417-6-aneesh.kumar@linux.ibm.com
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 arch/powerpc/mm/init_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 05b0d584e50b..fe1b83020e0d 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -189,7 +189,7 @@ static bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long star
 	unsigned long nr_pfn = page_size / sizeof(struct page);
 	unsigned long start_pfn = page_to_pfn((struct page *)start);
 
-	if ((start_pfn + nr_pfn) > altmap->end_pfn)
+	if ((start_pfn + nr_pfn - 1) > altmap->end_pfn)
 		return true;
 
 	if (start_pfn < altmap->base_pfn)
-- 
2.41.0