[PATCH v2 32/69] mm/mm_init: Factor out pfn_to_zone() as a shared helper

[Muchun Song]

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

Move it to mm_init.c, declare it in mm/internal.h, and reuse it from
__init_page_from_nid() 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, 17 insertions(+), 26 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index bf30617c78d8..18276cd15622 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -1354,6 +1354,7 @@ 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 6723c604eefd..35c99e5c215c 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -686,25 +686,29 @@ 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
 /*
  * Initialize a reserved page unconditionally, finding its zone first.
  */
 static void __meminit __init_page_from_nid(unsigned long pfn, int nid)
 {
-	pg_data_t *pgdat;
-	int zid;
-
-	pgdat = NODE_DATA(nid);
-
-	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);
+	struct zone *zone = pfn_to_zone(pfn, nid);
 
+	__init_single_page(pfn_to_page(pfn), pfn, zone_idx(zone), 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 b86634903fc0..f1c3b2d0f23c 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -138,20 +138,6 @@ 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