[PATCH v2 6/8] vmw_balloon: mark inflated pages PG_offline

[David Hildenbrand <david@xxxxxxxxxx>]

Mark inflated and never onlined pages PG_offline, to tell the world that
the content is stale and should not be dumped.

Cc: Xavier Deguillard <xdeguillard@xxxxxxxxxx>
Cc: Nadav Amit <namit@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Julien Freche <jfreche@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Acked-by: Nadav Amit <namit@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
 drivers/misc/vmw_balloon.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
index e6126a4b95d3..877611b5659b 100644
--- a/drivers/misc/vmw_balloon.c
+++ b/drivers/misc/vmw_balloon.c
@@ -556,6 +556,36 @@ vmballoon_page_in_frames(enum vmballoon_page_size_type page_size)
 	return 1 << vmballoon_page_order(page_size);
 }
 
+/**
+ * vmballoon_mark_page_offline() - mark a page as offline
+ * @page: pointer for the page.
+ * @page_size: the size of the page.
+ */
+static void
+vmballoon_mark_page_offline(struct page *page,
+			    enum vmballoon_page_size_type page_size)
+{
+	int i;
+
+	for (i = 0; i < vmballoon_page_in_frames(page_size); i++)
+		__SetPageOffline(page + i);
+}
+
+/**
+ * vmballoon_mark_page_online() - mark a page as online
+ * @page: pointer for the page.
+ * @page_size: the size of the page.
+ */
+static void
+vmballoon_mark_page_online(struct page *page,
+			   enum vmballoon_page_size_type page_size)
+{
+	int i;
+
+	for (i = 0; i < vmballoon_page_in_frames(page_size); i++)
+		__ClearPageOffline(page + i);
+}
+
 /**
  * vmballoon_send_get_target() - Retrieve desired balloon size from the host.
  *
@@ -612,6 +642,7 @@ static int vmballoon_alloc_page_list(struct vmballoon *b,
 					 ctl->page_size);
 
 		if (page) {
+			vmballoon_mark_page_offline(page, ctl->page_size);
 			/* Success. Add the page to the list and continue. */
 			list_add(&page->lru, &ctl->pages);
 			continue;
@@ -850,6 +881,7 @@ static void vmballoon_release_page_list(struct list_head *page_list,
 
 	list_for_each_entry_safe(page, tmp, page_list, lru) {
 		list_del(&page->lru);
+		vmballoon_mark_page_online(page, page_size);
 		__free_pages(page, vmballoon_page_order(page_size));
 	}
 
-- 
2.17.2