vsock/virtio: factor our the code to initialize and delete VQs

BugLink: https://bugs.launchpad.net/bugs/2049417

[ Upstream commit a103209 ]

Add virtio_vsock_vqs_init() and virtio_vsock_vqs_del() with the code
that was in virtio_vsock_probe() and virtio_vsock_remove to initialize
and delete VQs.

These new functions will be used in the next commit to support device
suspend/resume

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 53b08c4 ("vsock/virtio: initialize the_virtio_vsock before using VQs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

Author: stefano-garzarella

net/vmw_vsock/virtio_transport.c

@@ -566,67 +566,28 @@ static void virtio_transport_rx_work(struct work_struct *work)
 	mutex_unlock(&vsock->rx_lock);
 }
 
-static int virtio_vsock_probe(struct virtio_device *vdev)
+static int virtio_vsock_vqs_init(struct virtio_vsock *vsock)
 {
-	vq_callback_t *callbacks[] = {
-		virtio_vsock_rx_done,
-		virtio_vsock_tx_done,
-		virtio_vsock_event_done,
-	};
+	struct virtio_device *vdev = vsock->vdev;
 	static const char * const names[] = {
 		"rx",
 		"tx",
 		"event",
 	};
-	struct virtio_vsock *vsock = NULL;
+	vq_callback_t *callbacks[] = {
+		virtio_vsock_rx_done,
+		virtio_vsock_tx_done,
+		virtio_vsock_event_done,
+	};
 	int ret;
 
-	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
-	if (ret)
-		return ret;
-
-	/* Only one virtio-vsock device per guest is supported */
-	if (rcu_dereference_protected(the_virtio_vsock,
-				lockdep_is_held(&the_virtio_vsock_mutex))) {
-		ret = -EBUSY;
-		goto out;
-	}
-
-	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
-	if (!vsock) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
-	vsock->vdev = vdev;
-
-	ret = virtio_find_vqs(vsock->vdev, VSOCK_VQ_MAX,
-			      vsock->vqs, callbacks, names,
+	ret = virtio_find_vqs(vdev, VSOCK_VQ_MAX, vsock->vqs, callbacks, names,
 			      NULL);
 	if (ret < 0)
-		goto out;
+		return ret;
 
 	virtio_vsock_update_guest_cid(vsock);
 
-	vsock->rx_buf_nr = 0;
-	vsock->rx_buf_max_nr = 0;
-	atomic_set(&vsock->queued_replies, 0);
-
-	mutex_init(&vsock->tx_lock);
-	mutex_init(&vsock->rx_lock);
-	mutex_init(&vsock->event_lock);
-	spin_lock_init(&vsock->send_pkt_list_lock);
-	INIT_LIST_HEAD(&vsock->send_pkt_list);
-	INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
-	INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
-	INIT_WORK(&vsock->event_work, virtio_transport_event_work);
-	INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
-
-	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
-		vsock->seqpacket_allow = true;
-
-	vdev->priv = vsock;
-
 	virtio_device_ready(vdev);
 
 	mutex_lock(&vsock->tx_lock);
@@ -643,30 +604,15 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 	vsock->event_run = true;
 	mutex_unlock(&vsock->event_lock);
 
-	rcu_assign_pointer(the_virtio_vsock, vsock);
-
-	mutex_unlock(&the_virtio_vsock_mutex);
-
 	return 0;
-
-out:
-	kfree(vsock);
-	mutex_unlock(&the_virtio_vsock_mutex);
-	return ret;
 }
 
-static void virtio_vsock_remove(struct virtio_device *vdev)
+static void virtio_vsock_vqs_del(struct virtio_vsock *vsock)
 {
-	struct virtio_vsock *vsock = vdev->priv;
+	struct virtio_device *vdev = vsock->vdev;
 	struct virtio_vsock_pkt *pkt;
 
-	mutex_lock(&the_virtio_vsock_mutex);
-
-	vdev->priv = NULL;
-	rcu_assign_pointer(the_virtio_vsock, NULL);
-	synchronize_rcu();
-
-	/* Reset all connected sockets when the device disappear */
+	/* Reset all connected sockets when the VQs disappear */
 	vsock_for_each_connected_socket(&virtio_transport.transport,
 					virtio_vsock_reset_sock);
 
@@ -711,6 +657,78 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
 
 	/* Delete virtqueues and flush outstanding callbacks if any */
 	vdev->config->del_vqs(vdev);
+}
+
+static int virtio_vsock_probe(struct virtio_device *vdev)
+{
+	struct virtio_vsock *vsock = NULL;
+	int ret;
+
+	ret = mutex_lock_interruptible(&the_virtio_vsock_mutex);
+	if (ret)
+		return ret;
+
+	/* Only one virtio-vsock device per guest is supported */
+	if (rcu_dereference_protected(the_virtio_vsock,
+				lockdep_is_held(&the_virtio_vsock_mutex))) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	vsock = kzalloc(sizeof(*vsock), GFP_KERNEL);
+	if (!vsock) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	vsock->vdev = vdev;
+
+	vsock->rx_buf_nr = 0;
+	vsock->rx_buf_max_nr = 0;
+	atomic_set(&vsock->queued_replies, 0);
+
+	mutex_init(&vsock->tx_lock);
+	mutex_init(&vsock->rx_lock);
+	mutex_init(&vsock->event_lock);
+	spin_lock_init(&vsock->send_pkt_list_lock);
+	INIT_LIST_HEAD(&vsock->send_pkt_list);
+	INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
+	INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
+	INIT_WORK(&vsock->event_work, virtio_transport_event_work);
+	INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
+
+	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
+		vsock->seqpacket_allow = true;
+
+	vdev->priv = vsock;
+
+	ret = virtio_vsock_vqs_init(vsock);
+	if (ret < 0)
+		goto out;
+
+	rcu_assign_pointer(the_virtio_vsock, vsock);
+
+	mutex_unlock(&the_virtio_vsock_mutex);
+
+	return 0;
+
+out:
+	kfree(vsock);
+	mutex_unlock(&the_virtio_vsock_mutex);
+	return ret;
+}
+
+static void virtio_vsock_remove(struct virtio_device *vdev)
+{
+	struct virtio_vsock *vsock = vdev->priv;
+
+	mutex_lock(&the_virtio_vsock_mutex);
+
+	vdev->priv = NULL;
+	rcu_assign_pointer(the_virtio_vsock, NULL);
+	synchronize_rcu();
+
+	virtio_vsock_vqs_del(vsock);
 
 	/* Other works can be queued before 'config->del_vqs()', so we flush
 	 * all works before to free the vsock object to avoid use after free.