virtio: blk: Add freeze, restore handlers to support S4

Delete the vq and flush any pending requests from the block queue 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>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index e8af52355bf54e2192cc2f28ddf75b9ab9c9b840..ffd5ca919295fd171b6dcc9217f0aed0a600375f 100644 (file)
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -588,6 +588,46 @@ static void __devexit virtblk_remove(struct virtio_device *vdev)
        ida_simple_remove(&vd_index_ida, index);
 }
 
+#ifdef CONFIG_PM
+static int virtblk_freeze(struct virtio_device *vdev)
+{
+       struct virtio_blk *vblk = vdev->priv;
+
+       /* Ensure we don't receive any more interrupts */
+       vdev->config->reset(vdev);
+
+       /* Prevent config work handler from accessing the device. */
+       mutex_lock(&vblk->config_lock);
+       vblk->config_enable = false;
+       mutex_unlock(&vblk->config_lock);
+
+       flush_work(&vblk->config_work);
+
+       spin_lock_irq(vblk->disk->queue->queue_lock);
+       blk_stop_queue(vblk->disk->queue);
+       spin_unlock_irq(vblk->disk->queue->queue_lock);
+       blk_sync_queue(vblk->disk->queue);
+
+       vdev->config->del_vqs(vdev);
+       return 0;
+}
+
+static int virtblk_restore(struct virtio_device *vdev)
+{
+       struct virtio_blk *vblk = vdev->priv;
+       int ret;
+
+       vblk->config_enable = true;
+       ret = init_vq(vdev->priv);
+       if (!ret) {
+               spin_lock_irq(vblk->disk->queue->queue_lock);
+               blk_start_queue(vblk->disk->queue);
+               spin_unlock_irq(vblk->disk->queue->queue_lock);
+       }
+       return ret;
+}
+#endif
+
 static const struct virtio_device_id id_table[] = {
        { VIRTIO_ID_BLOCK, VIRTIO_DEV_ANY_ID },
        { 0 },
@@ -613,6 +653,10 @@ 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)