[PATCH v2] mm/sparse.c: Use kvmalloc_node/kvfree to alloc/free memmap for the classic sparse

[Baoquan He <bhe@redhat.com>]

This change makes populate_section_memmap()/depopulate_section_memmap
much simpler.

Suggested-by: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Baoquan He <bhe@redhat.com>
---
v1->v2:
  The old version only used __get_free_pages() to replace alloc_pages()
  in populate_section_memmap().
  http://lkml.kernel.org/r/20200307084229.28251-8-bhe@redhat.com

 mm/sparse.c | 27 +++------------------------
 1 file changed, 3 insertions(+), 24 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index bf6c00a28045..362018e82e22 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -734,35 +734,14 @@ static void free_map_bootmem(struct page *memmap)
 struct page * __meminit populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
-	struct page *page, *ret;
-	unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
-
-	page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
-	if (page)
-		goto got_map_page;
-
-	ret = vmalloc(memmap_size);
-	if (ret)
-		goto got_map_ptr;
-
-	return NULL;
-got_map_page:
-	ret = (struct page *)pfn_to_kaddr(page_to_pfn(page));
-got_map_ptr:
-
-	return ret;
+	return kvmalloc_node(sizeof(struct page) * PAGES_PER_SECTION,
+			     GFP_KERNEL|__GFP_NOWARN, nid);
 }
 
 static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
 		struct vmem_altmap *altmap)
 {
-	struct page *memmap = pfn_to_page(pfn);
-
-	if (is_vmalloc_addr(memmap))
-		vfree(memmap);
-	else
-		free_pages((unsigned long)memmap,
-			   get_order(sizeof(struct page) * PAGES_PER_SECTION));
+	kvfree(pfn_to_page(pfn));
 }
 
 static void free_map_bootmem(struct page *memmap)
-- 
2.17.2