[PATCH 41/49] mm/sparse: simplify section_vmemmap_pages()

[Muchun Song]

After unifying DAX and HugeTLB vmemmap optimizations, we can now
simplify section_vmemmap_pages().

Previously, section_vmemmap_pages() needed to take altmap and pgmap
arguments to determine if vmemmap optimization was enabled. However,
sparse_add_section() already sets the section order using
section_set_order(ms, pgmap->vmemmap_shift) if vmemmap_can_optimize()
is true and the size is aligned to PAGES_PER_SECTION.

As a result, section_vmemmap_optimizable(ms) is sufficient to determine
if the section can be optimized, and section_order(ms) can directly
provide the order, making the altmap and pgmap arguments redundant.

Remove the unused altmap and pgmap arguments from
section_vmemmap_pages().

Signed-off-by: Muchun Song <songmuchun at bytedance.com>
---
 mm/internal.h       |  3 +--
 mm/sparse-vmemmap.c |  8 +++-----
 mm/sparse.c         | 18 ++++++------------
 3 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index b569d8309f4d..7f0731e5c84f 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -998,8 +998,7 @@ static inline void __section_mark_present(struct mem_section *ms,
 	ms->section_mem_map |= SECTION_MARKED_PRESENT;
 }
 
-int section_vmemmap_pages(unsigned long pfn, unsigned long nr_pages,
-			  struct vmem_altmap *altmap, struct dev_pagemap *pgmap);
+int section_vmemmap_pages(unsigned long pfn, unsigned long nr_pages);
 #else
 static inline void memblocks_present(void) {}
 static inline void sparse_init(void) {}
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index ba8c0c64f160..ac2efba9ef92 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -608,12 +608,10 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
 	 * section_activate() and pfn_valid() .
 	 */
 	if (!section_is_early) {
-		memmap_pages_add(-section_vmemmap_pages(pfn, nr_pages, altmap,
-							pgmap));
+		memmap_pages_add(-section_vmemmap_pages(pfn, nr_pages));
 		depopulate_section_memmap(pfn, nr_pages, altmap);
 	} else if (memmap) {
-		memmap_pages_add(-section_vmemmap_pages(pfn, nr_pages, altmap,
-							pgmap));
+		memmap_pages_add(-section_vmemmap_pages(pfn, nr_pages));
 		free_map_bootmem(memmap);
 	}
 
@@ -658,7 +656,7 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,
 		return pfn_to_page(pfn);
 
 	memmap = populate_section_memmap(pfn, nr_pages, nid, altmap, pgmap);
-	memmap_pages_add(section_vmemmap_pages(pfn, nr_pages, altmap, pgmap));
+	memmap_pages_add(section_vmemmap_pages(pfn, nr_pages));
 	if (!memmap) {
 		section_deactivate(pfn, nr_pages, altmap, pgmap);
 		return ERR_PTR(-ENOMEM);
diff --git a/mm/sparse.c b/mm/sparse.c
index 04c641b97325..163bb17bba96 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -345,28 +345,23 @@ static void __init sparse_usage_fini(void)
 	sparse_usagebuf = sparse_usagebuf_end = NULL;
 }
 
-int __meminit section_vmemmap_pages(unsigned long pfn, unsigned long nr_pages,
-				    struct vmem_altmap *altmap, struct dev_pagemap *pgmap)
+int __meminit section_vmemmap_pages(unsigned long pfn, unsigned long nr_pages)
 {
 	const struct mem_section *ms = __pfn_to_section(pfn);
-	unsigned int order = pgmap ? pgmap->vmemmap_shift : section_order(ms);
+	unsigned int order = section_order(ms);
 	unsigned long pages_per_compound = 1L << order;
-	unsigned int vmemmap_pages = OPTIMIZED_FOLIO_VMEMMAP_PAGES;
-
-	if (vmemmap_can_optimize(altmap, pgmap))
-		vmemmap_pages = VMEMMAP_RESERVE_NR;
 
 	VM_BUG_ON(!IS_ALIGNED(pfn | nr_pages, min(pages_per_compound, PAGES_PER_SECTION)));
 	VM_BUG_ON(pfn_to_section_nr(pfn) != pfn_to_section_nr(pfn + nr_pages - 1));
 
-	if (!vmemmap_can_optimize(altmap, pgmap) && !section_vmemmap_optimizable(ms))
+	if (!section_vmemmap_optimizable(ms))
 		return DIV_ROUND_UP(nr_pages * sizeof(struct page), PAGE_SIZE);
 
 	if (order < PFN_SECTION_SHIFT)
-		return vmemmap_pages * nr_pages / pages_per_compound;
+		return OPTIMIZED_FOLIO_VMEMMAP_PAGES * nr_pages / pages_per_compound;
 
 	if (IS_ALIGNED(pfn, pages_per_compound))
-		return vmemmap_pages;
+		return OPTIMIZED_FOLIO_VMEMMAP_PAGES;
 
 	return 0;
 }
@@ -396,8 +391,7 @@ static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
 						nid, NULL, NULL);
 		if (!map)
 			panic("Populate section (%ld) on node[%d] failed\n", pnum, nid);
-		memmap_boot_pages_add(section_vmemmap_pages(pfn, PAGES_PER_SECTION,
-							    NULL, NULL));
+		memmap_boot_pages_add(section_vmemmap_pages(pfn, PAGES_PER_SECTION));
 		sparse_init_early_section(nid, map, pnum, 0);
 	}
 	sparse_usage_fini();
-- 
2.20.1