1 files changed, 21 insertions, 7 deletions

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index ca2723d47338..b8c11e063ff0 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1483,17 +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;
@@ -1509,10 +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;
+        }
 }
 
 /*
@@ -1839,6 +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;
 
@@ -1849,10 +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;