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>

1 files changed, 44 insertions, 0 deletions

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index e8af52355bf5..ffd5ca919295 100644
--- 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)