[PATCH 5.3 26/95] virtio_balloon: fix shrinker count

[Greg Kroah-Hartman]

From: Wei Wang <wei.w.wang@xxxxxxxxx>

commit c9a6820fc0da2603be3054ee7590eb9f350508a7 upstream.

Instead of multiplying by page order, virtio balloon divided by page
order. The result is that it can return 0 if there are a bit less
than MAX_ORDER - 1 pages in use, and then shrinker scan won't be called.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker")
Signed-off-by: Wei Wang <wei.w.wang@xxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/virtio/virtio_balloon.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -820,7 +820,7 @@ static unsigned long virtio_balloon_shri
 	unsigned long count;
 
 	count = vb->num_pages / VIRTIO_BALLOON_PAGES_PER_PAGE;
-	count += vb->num_free_page_blocks >> VIRTIO_BALLOON_FREE_PAGE_ORDER;
+	count += vb->num_free_page_blocks << VIRTIO_BALLOON_FREE_PAGE_ORDER;
 
 	return count;
 }