[PATCH v5 06/17] mm/mm_init: factor out pfn_to_zone()

[Muchun Song <songmuchun@bytedance.com>]

pfn_to_zone() in hugetlb_vmemmap.c duplicates the zone lookup logic in
__init_deferred_page().

Move it to mm_init.c, declare it in mm/mm_init.h, and reuse it from
__init_deferred_page() and HugeTLB early vmemmap initialization instead
of open-coding the zone walk there.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
v3:
- Fix the commit message to name mm/mm_init.h instead of mm/internal.h
- Collect Acked-by from Mike Rapoport

v2:
- Move this preparatory patch before the sparse-vmemmap optimization
  changes (suggested by Mike Rapoport)
---
 mm/hugetlb_vmemmap.c | 17 ++---------------
 mm/mm_init.c         | 28 ++++++++++++++++++----------
 mm/mm_init.h         |  1 +
 3 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index ae8fdaa42118..c48fcea076a5 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -19,6 +19,7 @@
 #include <asm/tlbflush.h>
 #include "hugetlb_vmemmap.h"
 #include "internal.h"
+#include "mm_init.h"
 
 /**
  * struct vmemmap_remap_walk - walk vmemmap page table
@@ -744,20 +745,6 @@ static bool vmemmap_should_optimize_bootmem_page(struct huge_bootmem_page *m)
 	return true;
 }
 
-static struct zone *pfn_to_zone(unsigned nid, unsigned long pfn)
-{
-	struct zone *zone;
-	enum zone_type zone_type;
-
-	for (zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
-		zone = &NODE_DATA(nid)->node_zones[zone_type];
-		if (zone_spans_pfn(zone, pfn))
-			return zone;
-	}
-
-	return NULL;
-}
-
 /*
  * Initialize memmap section for a gigantic page, HVO-style.
  */
@@ -787,7 +774,7 @@ void __init hugetlb_vmemmap_init_early(int nid)
 		map = pfn_to_page(pfn);
 		start = (unsigned long)map;
 		end = start + hugetlb_vmemmap_size(m->hstate);
-		zone = pfn_to_zone(nid, pfn);
+		zone = pfn_to_zone(pfn, nid);
 
 		if (vmemmap_populate_hvo(start, end, huge_page_order(m->hstate),
 					 zone, HUGETLB_VMEMMAP_RESERVE_SIZE))
diff --git a/mm/mm_init.c b/mm/mm_init.c
index f801fd486085..0317fb781e77 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -692,6 +692,20 @@ static __meminit void pageblock_migratetype_init_range(unsigned long pfn,
 	}
 }
 
+struct zone __meminit *pfn_to_zone(unsigned long pfn, int nid)
+{
+	pg_data_t *pgdat = NODE_DATA(nid);
+
+	for (enum zone_type zone_type = 0; zone_type < MAX_NR_ZONES; zone_type++) {
+		struct zone *zone = &pgdat->node_zones[zone_type];
+
+		if (zone_spans_pfn(zone, pfn))
+			return zone;
+	}
+
+	return NULL;
+}
+
 #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
 static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
 {
@@ -750,20 +764,14 @@ defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
 
 static void __meminit __init_deferred_page(unsigned long pfn, int nid)
 {
-	pg_data_t *pgdat = NODE_DATA(nid);
-	int zid;
+	struct zone *zone;
 
 	if (early_page_initialised(pfn, nid))
 		return;
 
-	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
-		struct zone *zone = &pgdat->node_zones[zid];
-
-		if (zone_spans_pfn(zone, pfn))
-			break;
-	}
-	__init_single_page(pfn_to_page(pfn), pfn, zid, nid);
-
+	zone = pfn_to_zone(pfn, nid);
+	__init_single_page(pfn_to_page(pfn), pfn,
+			   zone ? zone_idx(zone) : MAX_NR_ZONES, nid);
 	if (pageblock_aligned(pfn)) {
 		enum migratetype mt =
 			kho_scratch_migratetype(pfn, MIGRATE_MOVABLE);
diff --git a/mm/mm_init.h b/mm/mm_init.h
index 39f75df9be1c..c9fc35e7e9f1 100644
--- a/mm/mm_init.h
+++ b/mm/mm_init.h
@@ -39,6 +39,7 @@ void memmap_init_range(unsigned long size, int nid, unsigned long zone,
 		enum meminit_context context,
 		struct vmem_altmap *altmap, int migratetype,
 		bool isolate_pageblock);
+struct zone *pfn_to_zone(unsigned long pfn, int nid);
 
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 /* Free whole pageblock and set its migration type to MIGRATE_CMA. */
-- 
2.54.0