[PATCH 10/17] mm/mm_init: factor out pfn_to_zone()

[Muchun Song]

pfn_to_zone() in sparse-vmemmap.c duplicates the zone lookup logic in
__init_deferred_page().

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

Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
 mm/internal.h       |  1 +
 mm/mm_init.c        | 28 ++++++++++++++++++----------
 mm/sparse-vmemmap.c | 14 --------------
 3 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index 11844b40f47a..1348c8bb18e0 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1360,6 +1360,7 @@ static inline bool deferred_pages_enabled(void)
 }
 #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
 
+struct zone *pfn_to_zone(unsigned long pfn, int nid);
 void init_deferred_page(unsigned long pfn, int nid);
 
 enum mminit_level {
diff --git a/mm/mm_init.c b/mm/mm_init.c
index 0256ab4ba839..69ececb591e2 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -689,6 +689,20 @@ 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)
 {
@@ -747,20 +761,14 @@ 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/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 90aa11c472d6..37afd5ccf260 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -144,20 +144,6 @@ void __meminit vmemmap_verify(pte_t *pte, int node,
 			start, end - 1);
 }
 
-static 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;
-}
-
 static __meminit struct page *vmemmap_get_tail(unsigned int order, struct zone *zone);
 
 static pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
-- 
2.54.0