[RFC PATCH 2/8] virtio-pci: add PM notification handlers for restore, freeze, thaw, poweroff

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

Handle restore and freeze notification from the PM core.  Expose these
to individual virtio drivers that can quiesce and resume vq operations.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 drivers/virtio/virtio_pci.c |   34 ++++++++++++++++++++++++++++++++++
 include/linux/virtio.h      |    4 ++++
 2 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index 3879c3e..579681f 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -704,9 +704,43 @@ static int virtio_pci_resume(struct device *dev)
 	return 0;
 }
 
+static int virtio_pci_freeze(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct virtio_driver *drv;
+
+	drv = container_of(vp_dev->vdev.dev.driver,
+			   struct virtio_driver, driver);
+
+	if (drv && drv->freeze)
+		return drv->freeze(&vp_dev->vdev);
+
+	return 0;
+}
+
+static int virtio_pci_restore(struct device *dev)
+{
+	struct pci_dev *pci_dev = to_pci_dev(dev);
+	struct virtio_pci_device *vp_dev = pci_get_drvdata(pci_dev);
+	struct virtio_driver *drv;
+
+	drv = container_of(vp_dev->vdev.dev.driver,
+			   struct virtio_driver, driver);
+
+	if (drv && drv->restore)
+		return drv->restore(&vp_dev->vdev);
+
+	return 0;
+}
+
 static const struct dev_pm_ops virtio_pci_pm_ops = {
 	.suspend = virtio_pci_suspend,
 	.resume  = virtio_pci_resume,
+	.freeze  = virtio_pci_freeze,
+	.thaw    = virtio_pci_restore,
+	.restore = virtio_pci_restore,
+	.poweroff = virtio_pci_suspend,
 };
 #endif
 
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 7108857..9afb662 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -141,6 +141,10 @@ struct virtio_driver {
 	int (*probe)(struct virtio_device *dev);
 	void (*remove)(struct virtio_device *dev);
 	void (*config_changed)(struct virtio_device *dev);
+#ifdef CONFIG_PM
+	int (*freeze)(struct virtio_device *dev);
+	int (*restore)(struct virtio_device *dev);
+#endif
 };
 
 int register_virtio_driver(struct virtio_driver *drv);
-- 
1.7.6