[PATCH] virtio_pmem: Add freeze/restore callbacks

[Philip Chen]

Add basic freeze/restore PM callbacks to support hibernation (S4):
- On freeze, delete vq and quiesce the device to prepare for
  snapshotting.
- On restore, re-init vq and mark DRIVER_OK.

Signed-off-by: Philip Chen <philipc...@chromium.org>
---
 drivers/nvdimm/virtio_pmem.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/nvdimm/virtio_pmem.c b/drivers/nvdimm/virtio_pmem.c
index c9b97aeabf85..2396d19ce549 100644
--- a/drivers/nvdimm/virtio_pmem.c
+++ b/drivers/nvdimm/virtio_pmem.c
@@ -143,6 +143,28 @@ static void virtio_pmem_remove(struct virtio_device *vdev)
        virtio_reset_device(vdev);
 }
 
+static int virtio_pmem_freeze(struct virtio_device *vdev)
+{
+       vdev->config->del_vqs(vdev);
+       virtio_reset_device(vdev);
+
+       return 0;
+}
+
+static int virtio_pmem_restore(struct virtio_device *vdev)
+{
+       int ret;
+
+       ret = init_vq(vdev->priv);
+       if (ret) {
+               dev_err(&vdev->dev, "failed to initialize virtio pmem's vq\n");
+               return ret;
+       }
+       virtio_device_ready(vdev);
+
+       return 0;
+}
+
 static unsigned int features[] = {
        VIRTIO_PMEM_F_SHMEM_REGION,
 };
@@ -155,6 +177,8 @@ static struct virtio_driver virtio_pmem_driver = {
        .validate               = virtio_pmem_validate,
        .probe                  = virtio_pmem_probe,
        .remove                 = virtio_pmem_remove,
+       .freeze                 = virtio_pmem_freeze,
+       .restore                = virtio_pmem_restore,
 };
 
 module_virtio_driver(virtio_pmem_driver);
-- 
2.46.0.76.ge559c4bf1a-goog