[PATCH 2/4] powerpc/mm: drop powerpc vmemmap_can_optimize()

[Muchun Song]

PowerPC no longer needs an architecture-specific vmemmap_can_optimize()
override for DAX vmemmap optimization.

Whether the optimized mapping can be used is now decided in the
architecture-specific vmemmap_populate() path. When PowerPC has to fall
back, such as on Hash MMU, it can simply clear the section compound order
there and disable the optimization for that section.

Drop the radix-specific vmemmap_can_optimize() override and rely on the
generic checks instead.

Signed-off-by: Muchun Song <songmuchun at bytedance.com>
---
 arch/powerpc/include/asm/book3s/64/radix.h |  5 -----
 arch/powerpc/mm/book3s64/radix_pgtable.c   | 10 ----------
 arch/powerpc/mm/init_64.c                  |  1 +
 3 files changed, 1 insertion(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 8452a2714cb1..df67209b0c5b 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -351,10 +351,5 @@ int radix__create_section_mapping(unsigned long start, unsigned long end,
 				  int nid, pgprot_t prot);
 int radix__remove_section_mapping(unsigned long start, unsigned long end);
 #endif /* CONFIG_MEMORY_HOTPLUG */
-
-#ifdef CONFIG_ARCH_WANT_OPTIMIZE_DAX_VMEMMAP
-#define vmemmap_can_optimize vmemmap_can_optimize
-bool vmemmap_can_optimize(struct vmem_altmap *altmap, struct dev_pagemap *pgmap);
-#endif
 #endif /* __ASSEMBLER__ */
 #endif
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index 2924604fbb38..63f369d296b4 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -978,16 +978,6 @@ int __meminit radix__vmemmap_create_mapping(unsigned long start,
 	return 0;
 }
 
-#ifdef CONFIG_ARCH_WANT_OPTIMIZE_DAX_VMEMMAP
-bool vmemmap_can_optimize(struct vmem_altmap *altmap, struct dev_pagemap *pgmap)
-{
-	if (radix_enabled())
-		return __vmemmap_can_optimize(altmap, pgmap);
-
-	return false;
-}
-#endif
-
 int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,
 				unsigned long addr, unsigned long next)
 {
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 0e777d7dc332..509cc4190db7 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -282,6 +282,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 		return radix__vmemmap_populate(start, end, node, altmap);
 #endif
 
+	section_set_compound_order(__pfn_to_section(page_to_pfn((struct page *)start)), 0);
 	return __vmemmap_populate(start, end, node, altmap);
 }
 
-- 
2.54.0