Thread (3 messages) flat view 3 messages, 3 authors, 2016-07-20
STALE3682d

[PATCH resend] virtio-net: Remove more stack DMA

From: Andy Lutomirski <luto@kernel.org>
Date: 2016-07-18 22:34:57
Also in: lkml
Subsystem: networking drivers, the rest, virtio net driver · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, "Michael S. Tsirkin", Jason Wang

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

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: "netdev@vger.kernel.org" <redacted>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---

I tested VLAN addition and removal with CONFIG_VMAP_STACK=y,
CONFIG_DEBUG_SG=y and it got rid of the warnings I saw.  I haven't
tested the MQ part because I don't know how to enable it in the first
place (I'm guessing it needs me to enable some QEMU feature I don't
know about.)

DaveM, contrary to what I thought last time I sent this, I think this
should go through net-next as long as it makes it in time for 4.8.

 drivers/net/virtio_net.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index e0638e556fe7..5044ca37d725 100644
--- a/drivers/net/virtio_net.c
+++ b/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;
@@ -1116,14 +1118,13 @@ 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)) {
@@ -1230,7 +1231,8 @@ 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))
@@ -1244,7 +1246,8 @@ 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))
-- 
2.7.4
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