[RFC PATCH 7/8] virtio: block: Add freeze, restore handlers to support S4

[Amit Shah <amit.shah@redhat.com>]

Delete the vq on the freeze callback to prepare for hibernation.
Re-create the vq in the restore callback to resume normal function.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 drivers/block/virtio_blk.c |   24 ++++++++++++++++++++++++
 1 files changed, 24 insertions(+), 0 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 079c088..700ad76 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -540,6 +540,26 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
 	kfree(vblk);
 }
 
+#ifdef CONFIG_PM
+static int virtblk_freeze(struct virtio_device *vdev)
+{
+	vdev->config->del_vqs(vdev);
+	return 0;
+}
+
+static int virtblk_restore(struct virtio_device *vdev)
+{
+	struct virtio_blk *vblk = vdev->priv;
+	int err = 0;
+
+	vblk->vq = virtio_find_single_vq(vdev, blk_done, "requests");
+	if (IS_ERR(vblk->vq))
+		err = PTR_ERR(vblk->vq);
+
+	return err;
+}
+#endif
+
 static const struct virtio_device_id id_table[] = {
 	{ VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
 	{ 0 },
@@ -565,6 +585,10 @@ static struct virtio_driver __refdata virtio_blk = {
 	.probe			= virtblk_probe,
 	.remove			= __devexit_p(virtblk_remove),
 	.config_changed		= virtblk_config_changed,
+#ifdef CONFIG_PM
+	.freeze			= virtblk_freeze,
+	.restore		= virtblk_restore,
+#endif
 };
 
 static int __init init(void)
-- 
1.7.6