[5.12,029/700] mm/page_alloc: fix memory map initialization for descending nodes

--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2435,7 +2435,6 @@  extern void set_dma_reserve(unsigned lon
 extern void memmap_init_range(unsigned long, int, unsigned long,
 		unsigned long, unsigned long, enum meminit_context,
 		struct vmem_altmap *, int migratetype);
-extern void memmap_init_zone(struct zone *zone);
 extern void setup_per_zone_wmarks(void);
 extern int __meminit init_per_zone_wmark_min(void);
 extern void mem_init(void);
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6207,7 +6207,7 @@  void __ref memmap_init_zone_device(struc
 		return;
 
 	/*
-	 * The call to memmap_init_zone should have already taken care
+	 * The call to memmap_init should have already taken care
 	 * of the pages reserved for the memmap, so we can just jump to
 	 * the end of that region and start processing the device pages.
 	 */
@@ -6272,7 +6272,7 @@  static void __meminit zone_init_free_lis
 /*
  * Only struct pages that correspond to ranges defined by memblock.memory
  * are zeroed and initialized by going through __init_single_page() during
- * memmap_init_zone().
+ * memmap_init_zone_range().
  *
  * But, there could be struct pages that correspond to holes in
  * memblock.memory. This can happen because of the following reasons:
@@ -6291,9 +6291,9 @@  static void __meminit zone_init_free_lis
  *   zone/node above the hole except for the trailing pages in the last
  *   section that will be appended to the zone/node below.
  */
-static u64 __meminit init_unavailable_range(unsigned long spfn,
-					    unsigned long epfn,
-					    int zone, int node)
+static void __init init_unavailable_range(unsigned long spfn,
+					  unsigned long epfn,
+					  int zone, int node)
 {
 	unsigned long pfn;
 	u64 pgcnt = 0;
@@ -6309,56 +6309,77 @@  static u64 __meminit init_unavailable_ra
 		pgcnt++;
 	}
 
-	return pgcnt;
+	if (pgcnt)
+		pr_info("On node %d, zone %s: %lld pages in unavailable ranges",
+			node, zone_names[zone], pgcnt);
 }
 #else
-static inline u64 init_unavailable_range(unsigned long spfn, unsigned long epfn,
-					 int zone, int node)
+static inline void init_unavailable_range(unsigned long spfn,
+					  unsigned long epfn,
+					  int zone, int node)
 {
-	return 0;
 }
 #endif
 
-void __meminit __weak memmap_init_zone(struct zone *zone)
+static void __init memmap_init_zone_range(struct zone *zone,
+					  unsigned long start_pfn,
+					  unsigned long end_pfn,
+					  unsigned long *hole_pfn)
 {
 	unsigned long zone_start_pfn = zone->zone_start_pfn;
 	unsigned long zone_end_pfn = zone_start_pfn + zone->spanned_pages;
-	int i, nid = zone_to_nid(zone), zone_id = zone_idx(zone);
-	static unsigned long hole_pfn;
+	int nid = zone_to_nid(zone), zone_id = zone_idx(zone);
+
+	start_pfn = clamp(start_pfn, zone_start_pfn, zone_end_pfn);
+	end_pfn = clamp(end_pfn, zone_start_pfn, zone_end_pfn);
+
+	if (start_pfn >= end_pfn)
+		return;
+
+	memmap_init_range(end_pfn - start_pfn, nid, zone_id, start_pfn,
+			  zone_end_pfn, MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
+
+	if (*hole_pfn < start_pfn)
+		init_unavailable_range(*hole_pfn, start_pfn, zone_id, nid);
+
+	*hole_pfn = end_pfn;
+}
+
+static void __init memmap_init(void)
+{
 	unsigned long start_pfn, end_pfn;
-	u64 pgcnt = 0;
+	unsigned long hole_pfn = 0;
+	int i, j, zone_id, nid;
 
-	for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
-		start_pfn = clamp(start_pfn, zone_start_pfn, zone_end_pfn);
-		end_pfn = clamp(end_pfn, zone_start_pfn, zone_end_pfn);
+	for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, &nid) {
+		struct pglist_data *node = NODE_DATA(nid);
+
+		for (j = 0; j < MAX_NR_ZONES; j++) {
+			struct zone *zone = node->node_zones + j;
+
+			if (!populated_zone(zone))
+				continue;
 
-		if (end_pfn > start_pfn)
-			memmap_init_range(end_pfn - start_pfn, nid,
-					zone_id, start_pfn, zone_end_pfn,
-					MEMINIT_EARLY, NULL, MIGRATE_MOVABLE);
-
-		if (hole_pfn < start_pfn)
-			pgcnt += init_unavailable_range(hole_pfn, start_pfn,
-							zone_id, nid);
-		hole_pfn = end_pfn;
+			memmap_init_zone_range(zone, start_pfn, end_pfn,
+					       &hole_pfn);
+			zone_id = j;
+		}
 	}
 
 #ifdef CONFIG_SPARSEMEM
 	/*
-	 * Initialize the hole in the range [zone_end_pfn, section_end].
-	 * If zone boundary falls in the middle of a section, this hole
-	 * will be re-initialized during the call to this function for the
-	 * higher zone.
+	 * Initialize the memory map for hole in the range [memory_end,
+	 * section_end].
+	 * Append the pages in this hole to the highest zone in the last
+	 * node.
+	 * The call to init_unavailable_range() is outside the ifdef to
+	 * silence the compiler warining about zone_id set but not used;
+	 * for FLATMEM it is a nop anyway
 	 */
-	end_pfn = round_up(zone_end_pfn, PAGES_PER_SECTION);
+	end_pfn = round_up(end_pfn, PAGES_PER_SECTION);
 	if (hole_pfn < end_pfn)
-		pgcnt += init_unavailable_range(hole_pfn, end_pfn,
-						zone_id, nid);
 #endif
-
-	if (pgcnt)
-		pr_info("  %s zone: %llu pages in unavailable ranges\n",
-			zone->name, pgcnt);
+		init_unavailable_range(hole_pfn, end_pfn, zone_id, nid);
 }
 
 static int zone_batchsize(struct zone *zone)
@@ -7061,7 +7082,6 @@  static void __init free_area_init_core(s
 		set_pageblock_order();
 		setup_usemap(zone);
 		init_currently_empty_zone(zone, zone->zone_start_pfn, size);
-		memmap_init_zone(zone);
 	}
 }
 
@@ -7587,6 +7607,8 @@  void __init free_area_init(unsigned long
 			node_set_state(nid, N_MEMORY);
 		check_for_memory(pgdat, nid);
 	}
+
+	memmap_init();
 }
 
 static int __init cmdline_parse_core(char *p, unsigned long *core,