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-rw-r--r--mm/memory_hotplug.c28
1 files changed, 26 insertions, 2 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 84ab3298cce9..fee3bacdd700 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1485,10 +1485,19 @@ static void node_states_clear_node(int node, struct memory_notify *arg)
node_clear_state(node, N_MEMORY);
}
+static int count_system_ram_pages_cb(unsigned long start_pfn,
+ unsigned long nr_pages, void *data)
+{
+ unsigned long *nr_system_ram_pages = data;
+
+ *nr_system_ram_pages += nr_pages;
+ return 0;
+}
+
static int __ref __offline_pages(unsigned long start_pfn,
unsigned long end_pfn)
{
- unsigned long pfn, nr_pages;
+ unsigned long pfn, nr_pages = 0;
unsigned long offlined_pages = 0;
int ret, node, nr_isolate_pageblock;
unsigned long flags;
@@ -1499,6 +1508,22 @@ static int __ref __offline_pages(unsigned long start_pfn,
mem_hotplug_begin();
+ /*
+ * Don't allow to offline memory blocks that contain holes.
+ * Consequently, memory blocks with holes can never get onlined
+ * via the hotplug path - online_pages() - as hotplugged memory has
+ * no holes. This way, we e.g., don't have to worry about marking
+ * memory holes PG_reserved, don't need pfn_valid() checks, and can
+ * avoid using walk_system_ram_range() later.
+ */
+ walk_system_ram_range(start_pfn, end_pfn - start_pfn, &nr_pages,
+ count_system_ram_pages_cb);
+ if (nr_pages != end_pfn - start_pfn) {
+ ret = -EINVAL;
+ reason = "memory holes";
+ goto failed_removal;
+ }
+
/* This makes hotplug much easier...and readable.
we assume this for now. .*/
if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
@@ -1510,7 +1535,6 @@ static int __ref __offline_pages(unsigned long start_pfn,
zone = page_zone(pfn_to_page(valid_start));
node = zone_to_nid(zone);
- nr_pages = end_pfn - start_pfn;
/* set above range as isolated */
ret = start_isolate_page_range(start_pfn, end_pfn,