[PATCH 6.4 492/800] powerpc/mm/dax: Fix the condition when checking if altmap vmemap can cross-boundary

Greg Kroah-Hartman
2023-07-16T20:16:41Z

From: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>

[ Upstream 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
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 05b0d584e50b8..fe1b83020e0df 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)
--
2.39.2