virtio-net: Remove more stack DMA

VLAN and MQ control was doing DMA from the stack.  Fix it.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/virtio_net.c

@@ -144,8 +144,10 @@ struct virtnet_info {
 	/* Control VQ buffers: protected by the rtnl lock */
 	struct virtio_net_ctrl_hdr ctrl_hdr;
 	virtio_net_ctrl_ack ctrl_status;
+	struct virtio_net_ctrl_mq ctrl_mq;
 	u8 ctrl_promisc;
 	u8 ctrl_allmulti;
+	u16 ctrl_vid;
 
 	/* Ethtool settings */
 	u8 duplex;
@@ -1058,14 +1060,13 @@ static void virtnet_ack_link_announce(struct virtnet_info *vi)
 static int virtnet_set_queues(struct virtnet_info *vi, u16 queue_pairs)
 {
 	struct scatterlist sg;
-	struct virtio_net_ctrl_mq s;
 	struct net_device *dev = vi->dev;
 
 	if (!vi->has_cvq || !virtio_has_feature(vi->vdev, VIRTIO_NET_F_MQ))
 		return 0;
 
-	s.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
-	sg_init_one(&sg, &s, sizeof(s));
+	vi->ctrl_mq.virtqueue_pairs = cpu_to_virtio16(vi->vdev, queue_pairs);
+	sg_init_one(&sg, &vi->ctrl_mq, sizeof(vi->ctrl_mq));
 
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MQ,
 				  VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET, &sg)) {
@@ -1172,7 +1173,8 @@ static int virtnet_vlan_rx_add_vid(struct net_device *dev,
 	struct virtnet_info *vi = netdev_priv(dev);
 	struct scatterlist sg;
 
-	sg_init_one(&sg, &vid, sizeof(vid));
+	vi->ctrl_vid = vid;
+	sg_init_one(&sg, &vi->ctrl_vid, sizeof(vi->ctrl_vid));
 
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 				  VIRTIO_NET_CTRL_VLAN_ADD, &sg))
@@ -1186,7 +1188,8 @@ static int virtnet_vlan_rx_kill_vid(struct net_device *dev,
 	struct virtnet_info *vi = netdev_priv(dev);
 	struct scatterlist sg;
 
-	sg_init_one(&sg, &vid, sizeof(vid));
+	vi->ctrl_vid = vid;
+	sg_init_one(&sg, &vi->ctrl_vid, sizeof(vi->ctrl_vid));
 
 	if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_VLAN,
 				  VIRTIO_NET_CTRL_VLAN_DEL, &sg))