[PATCH] arm64: mm: fix max_mapnr is assigned the wrong value

[Muchun Song]

When we not use flat memory, the mem_map will be NULL and
pfn_to_page(max_pfn) is a pointer which is located in kernel space. So
max_mapnr is assigned a very large number(e.g., 0xffffxxxx_xxxxxxxx) - fix
it.

Signed-off-by: Muchun Song <smuc...@gmail.com>
---
 arch/arm64/mm/init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index bc02818fa48b..e86c21a44c88 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -535,7 +535,7 @@ void __init mem_init(void)
        else
                swiotlb_force = SWIOTLB_NO_FORCE;
 
-       set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
+       set_max_mapnr(max_pfn - PHYS_PFN_OFFSET);
 
 #ifndef CONFIG_SPARSEMEM_VMEMMAP
        free_unused_memmap();
-- 
2.17.1