Re: [PATCH] virtio_pmem: Add freeze/restore callbacks

[Philip Chen]

Hi maintainers,

Can anyone let me know if this patch makes sense?
Any comment/feedback is appreciated.
Thanks in advance!

On Wed, Aug 14, 2024 at 5:46 PM Philip Chen <philipchen@xxxxxxxxxxxx> wrote:
>
> 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 <philipchen@xxxxxxxxxxxx>
> ---
>  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
>