1 files changed, 38 insertions, 18 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e43142c15631..b8c11e063ff0 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1033,36 +1033,39 @@ static void node_states_set_node(int node, struct memory_notify *arg)
 	node_set_state(node, N_MEMORY);
 }
 
-int zone_can_shift(unsigned long pfn, unsigned long nr_pages,
-		   enum zone_type target)
+bool zone_can_shift(unsigned long pfn, unsigned long nr_pages,
+		   enum zone_type target, int *zone_shift)
 {
 	struct zone *zone = page_zone(pfn_to_page(pfn));
 	enum zone_type idx = zone_idx(zone);
 	int i;
 
+	*zone_shift = 0;
+
 	if (idx < target) {
 		/* pages must be at end of current zone */
 		if (pfn + nr_pages != zone_end_pfn(zone))
-			return 0;
+			return false;
 
 		/* no zones in use between current zone and target */
 		for (i = idx + 1; i < target; i++)
 			if (zone_is_initialized(zone - idx + i))
-				return 0;
+				return false;
 	}
 
 	if (target < idx) {
 		/* pages must be at beginning of current zone */
 		if (pfn != zone->zone_start_pfn)
-			return 0;
+			return false;
 
 		/* no zones in use between current zone and target */
 		for (i = target + 1; i < idx; i++)
 			if (zone_is_initialized(zone - idx + i))
-				return 0;
+				return false;
 	}
 
-	return target - idx;
+	*zone_shift = target - idx;
+	return true;
 }
 
 /* Must be protected by mem_hotplug_begin() */
@@ -1089,10 +1092,13 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
 	    !can_online_high_movable(zone))
 		return -EINVAL;
 
-	if (online_type == MMOP_ONLINE_KERNEL)
-		zone_shift = zone_can_shift(pfn, nr_pages, ZONE_NORMAL);
-	else if (online_type == MMOP_ONLINE_MOVABLE)
-		zone_shift = zone_can_shift(pfn, nr_pages, ZONE_MOVABLE);
+	if (online_type == MMOP_ONLINE_KERNEL) {
+		if (!zone_can_shift(pfn, nr_pages, ZONE_NORMAL, &zone_shift))
+			return -EINVAL;
+	} else if (online_type == MMOP_ONLINE_MOVABLE) {
+		if (!zone_can_shift(pfn, nr_pages, ZONE_MOVABLE, &zone_shift))
+			return -EINVAL;
+	}
 
 	zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
 	if (!zone)
@@ -1477,17 +1483,20 @@ bool is_mem_section_removable(unsigned long start_pfn, unsigned long nr_pages)
 }
 
 /*
- * Confirm all pages in a range [start, end) is belongs to the same zone.
+ * Confirm all pages in a range [start, end) belong to the same zone.
+ * When true, return its valid [start, end).
  */
-int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
+int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn,
+			 unsigned long *valid_start, unsigned long *valid_end)
 {
 	unsigned long pfn, sec_end_pfn;
+	unsigned long start, end;
 	struct zone *zone = NULL;
 	struct page *page;
 	int i;
-	for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn);
+	for (pfn = start_pfn, sec_end_pfn = SECTION_ALIGN_UP(start_pfn + 1);
 	     pfn < end_pfn;
-	     pfn = sec_end_pfn + 1, sec_end_pfn += PAGES_PER_SECTION) {
+	     pfn = sec_end_pfn, sec_end_pfn += PAGES_PER_SECTION) {
 		/* Make sure the memory section is present first */
 		if (!present_section_nr(pfn_to_section_nr(pfn)))
 			continue;
@@ -1503,10 +1512,20 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
 			page = pfn_to_page(pfn + i);
 			if (zone && page_zone(page) != zone)
 				return 0;
+			if (!zone)
+				start = pfn + i;
 			zone = page_zone(page);
+			end = pfn + MAX_ORDER_NR_PAGES;
 		}
 	}
-	return 1;
+
+	if (zone) {
+		*valid_start = start;
+		*valid_end = end;
+		return 1;
+	} else {
+		return 0;
+	}
 }
 
 /*
@@ -1833,6 +1852,7 @@ static int __ref __offline_pages(unsigned long start_pfn,
 	long offlined_pages;
 	int ret, drain, retry_max, node;
 	unsigned long flags;
+	unsigned long valid_start, valid_end;
 	struct zone *zone;
 	struct memory_notify arg;
 
@@ -1843,10 +1863,10 @@ static int __ref __offline_pages(unsigned long start_pfn,
 		return -EINVAL;
 	/* This makes hotplug much easier...and readable.
 	   we assume this for now. .*/
-	if (!test_pages_in_a_zone(start_pfn, end_pfn))
+	if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
 		return -EINVAL;
 
-	zone = page_zone(pfn_to_page(start_pfn));
+	zone = page_zone(pfn_to_page(valid_start));
 	node = zone_to_nid(zone);
 	nr_pages = end_pfn - start_pfn;