2 files changed, 17 insertions, 28 deletions

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 6e02ec103cc7..aa30a25c8d49 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -81,12 +81,6 @@ static void add_early_randomness(struct hwrng *rng)
 	unsigned char bytes[16];
 	int bytes_read;
 
-	/*
-	 * Currently only virtio-rng cannot return data during device
-	 * probe, and that's handled in virtio-rng.c itself.  If there
-	 * are more such devices, this call to rng_get_data can be
-	 * made conditional here instead of doing it per-device.
-	 */
 	bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);
 	if (bytes_read > 0)
 		add_device_randomness(bytes, bytes_read);
diff --git a/drivers/char/hw_random/virtio-rng.c b/drivers/char/hw_random/virtio-rng.c
index e9b15bc18b4d..0027137daa56 100644
--- a/drivers/char/hw_random/virtio-rng.c
+++ b/drivers/char/hw_random/virtio-rng.c
@@ -28,17 +28,16 @@
 static DEFINE_IDA(rng_index_ida);
 
 struct virtrng_info {
-	struct virtio_device *vdev;
 	struct hwrng hwrng;
 	struct virtqueue *vq;
-	unsigned int data_avail;
 	struct completion have_data;
-	bool busy;
 	char name[25];
+	unsigned int data_avail;
 	int index;
+	bool busy;
+	bool hwrng_register_done;
 };
 
-static bool probe_done;
 
 static void random_recv_done(struct virtqueue *vq)
 {
@@ -69,13 +68,6 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
 	int ret;
 	struct virtrng_info *vi = (struct virtrng_info *)rng->priv;
 
-	/*
-	 * Don't ask host for data till we're setup.  This call can
-	 * happen during hwrng_register(), after commit d9e7972619.
-	 */
-	if (unlikely(!probe_done))
-		return 0;
-
 	if (!vi->busy) {
 		vi->busy = true;
 		init_completion(&vi->have_data);
@@ -137,25 +129,17 @@ static int probe_common(struct virtio_device *vdev)
 		return err;
 	}
 
-	err = hwrng_register(&vi->hwrng);
-	if (err) {
-		vdev->config->del_vqs(vdev);
-		vi->vq = NULL;
-		kfree(vi);
-		ida_simple_remove(&rng_index_ida, index);
-		return err;
-	}
-
-	probe_done = true;
 	return 0;
 }
 
 static void remove_common(struct virtio_device *vdev)
 {
 	struct virtrng_info *vi = vdev->priv;
+
 	vdev->config->reset(vdev);
 	vi->busy = false;
-	hwrng_unregister(&vi->hwrng);
+	if (vi->hwrng_register_done)
+		hwrng_unregister(&vi->hwrng);
 	vdev->config->del_vqs(vdev);
 	ida_simple_remove(&rng_index_ida, vi->index);
 	kfree(vi);
@@ -171,6 +155,16 @@ static void virtrng_remove(struct virtio_device *vdev)
 	remove_common(vdev);
 }
 
+static void virtrng_scan(struct virtio_device *vdev)
+{
+	struct virtrng_info *vi = vdev->priv;
+	int err;
+
+	err = hwrng_register(&vi->hwrng);
+	if (!err)
+		vi->hwrng_register_done = true;
+}
+
 #ifdef CONFIG_PM_SLEEP
 static int virtrng_freeze(struct virtio_device *vdev)
 {
@@ -195,6 +189,7 @@ static struct virtio_driver virtio_rng_driver = {
 	.id_table =	id_table,
 	.probe =	virtrng_probe,
 	.remove =	virtrng_remove,
+	.scan =		virtrng_scan,
 #ifdef CONFIG_PM_SLEEP
 	.freeze =	virtrng_freeze,
 	.restore =	virtrng_restore,