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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Wei Wang <wei.w.wang@intel.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        David Hildenbrand <david@redhat.com>
Subject: [PATCH 5.3 26/95] virtio_balloon: fix shrinker count
Date:   Wed, 27 Nov 2019 21:31:43 +0100
Message-Id: <20191127202853.159506349@linuxfoundation.org>
In-Reply-To: <20191127202845.651587549@linuxfoundation.org>
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From: Wei Wang <wei.w.wang@intel.com>

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@vger.kernel.org
Fixes: 71994620bb25 ("virtio_balloon: replace oom notifier with shrinker")
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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;
 }