[PATCH v2 08/15] mm/bootmem_info: avoid using sparse_decode_mem_map()

["David Hildenbrand (Arm)" <david@kernel.org>]

With SPARSEMEM_VMEMMAP, we can just do a pfn_to_page(). It is not super
clear whether the start_pfn is properly aligned ... so let's just make
sure it is properly aligned to the start of the section.

We will soon might try to remove the bootmem info completely, for now,
just keep it working as is.

Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
---
 mm/bootmem_info.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/mm/bootmem_info.c b/mm/bootmem_info.c
index e61e08e24924..3d7675a3ae04 100644
--- a/mm/bootmem_info.c
+++ b/mm/bootmem_info.c
@@ -44,17 +44,16 @@ static void __init register_page_bootmem_info_section(unsigned long start_pfn)
 {
 	unsigned long mapsize, section_nr, i;
 	struct mem_section *ms;
-	struct page *page, *memmap;
 	struct mem_section_usage *usage;
+	struct page *page;
 
+	start_pfn = SECTION_ALIGN_DOWN(start_pfn);
 	section_nr = pfn_to_section_nr(start_pfn);
 	ms = __nr_to_section(section_nr);
 
-	memmap = sparse_decode_mem_map(ms->section_mem_map, section_nr);
-
 	if (!preinited_vmemmap_section(ms))
-		register_page_bootmem_memmap(section_nr, memmap,
-				PAGES_PER_SECTION);
+		register_page_bootmem_memmap(section_nr, pfn_to_page(start_pfn),
+					     PAGES_PER_SECTION);
 
 	usage = ms->usage;
 	page = virt_to_page(usage);

-- 
2.43.0