1 files changed, 15 insertions, 57 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index b1be791f772d..df570e5c71cc 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -436,67 +436,25 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
         zone_span_writeunlock(zone);
 }
 
-static void shrink_pgdat_span(struct pglist_data *pgdat,
-                              unsigned long start_pfn, unsigned long end_pfn)
+static void update_pgdat_span(struct pglist_data *pgdat)
 {
-        unsigned long pgdat_start_pfn = pgdat->node_start_pfn;
-        unsigned long p = pgdat_end_pfn(pgdat); /* pgdat_end_pfn namespace clash */
-        unsigned long pgdat_end_pfn = p;
-        unsigned long pfn;
-        int nid = pgdat->node_id;
-
-        if (pgdat_start_pfn == start_pfn) {
-                /*
-                 * If the section is smallest section in the pgdat, it need
-                 * shrink pgdat->node_start_pfn and pgdat->node_spanned_pages.
-                 * In this case, we find second smallest valid mem_section
-                 * for shrinking zone.
-                 */
-                pfn = find_smallest_section_pfn(nid, NULL, end_pfn,
-                                                pgdat_end_pfn);
-                if (pfn) {
-                        pgdat->node_start_pfn = pfn;
-                        pgdat->node_spanned_pages = pgdat_end_pfn - pfn;
-                }
-        } else if (pgdat_end_pfn == end_pfn) {
-                /*
-                 * If the section is biggest section in the pgdat, it need
-                 * shrink pgdat->node_spanned_pages.
-                 * In this case, we find second biggest valid mem_section for
-                 * shrinking zone.
-                 */
-                pfn = find_biggest_section_pfn(nid, NULL, pgdat_start_pfn,
-                                               start_pfn);
-                if (pfn)
-                        pgdat->node_spanned_pages = pfn - pgdat_start_pfn + 1;
-        }
-
-        /*
-         * If the section is not biggest or smallest mem_section in the pgdat,
-         * it only creates a hole in the pgdat. So in this case, we need not
-         * change the pgdat.
-         * But perhaps, the pgdat has only hole data. Thus it check the pgdat
-         * has only hole or not.
-         */
-        pfn = pgdat_start_pfn;
-        for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SUBSECTION) {
-                if (unlikely(!pfn_valid(pfn)))
-                        continue;
-
-                if (pfn_to_nid(pfn) != nid)
-                        continue;
+        unsigned long node_start_pfn = 0, node_end_pfn = 0;
+        struct zone *zone;
 
-                /* Skip range to be removed */
-                if (pfn >= start_pfn && pfn < end_pfn)
-                        continue;
+        for (zone = pgdat->node_zones;
+             zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
+                unsigned long zone_end_pfn = zone->zone_start_pfn +
+                                             zone->spanned_pages;
 
-                /* If we find valid section, we have nothing to do */
-                return;
+                /* No need to lock the zones, they can't change. */
+                if (zone_end_pfn > node_end_pfn)
+                        node_end_pfn = zone_end_pfn;
+                if (zone->zone_start_pfn < node_start_pfn)
+                        node_start_pfn = zone->zone_start_pfn;
         }
 
-        /* The pgdat has no valid section */
-        pgdat->node_start_pfn = 0;
-        pgdat->node_spanned_pages = 0;
+        pgdat->node_start_pfn = node_start_pfn;
+        pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
 }
 
 static void __remove_zone(struct zone *zone, unsigned long start_pfn,
@@ -507,7 +465,7 @@ static void __remove_zone(struct zone *zone, unsigned long start_pfn,
 
         pgdat_resize_lock(zone->zone_pgdat, &flags);
         shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
-        shrink_pgdat_span(pgdat, start_pfn, start_pfn + nr_pages);
+        update_pgdat_span(pgdat);
         pgdat_resize_unlock(zone->zone_pgdat, &flags);
 }