Merge branch 'virtio_mac'

Amos Kong says:

====================
Currenly mac is programmed byte by byte. This means that we
have an intermediate step where mac is wrong.

Third patch introduced a new vq control command to set mac
address, it's atomic.

V2: check return of sending command, delay eth_mac_addr()
V3: restore software address when fail to set hardware address
V4: split eth_mac_addr, fix error handle
V5: rebase patches to net-next tree
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/virtio_net.c

@@ -753,19 +753,77 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 	return NETDEV_TX_OK;
 }
 
+/*
+ * Send command via the control virtqueue and check status.  Commands
+ * supported by the hypervisor, as indicated by feature bits, should
+ * never fail unless improperly formated.
+ */
+static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
+				 struct scatterlist *data, int out, int in)
+{
+	struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
+	struct virtio_net_ctrl_hdr ctrl;
+	virtio_net_ctrl_ack status = ~0;
+	unsigned int tmp;
+	int i;
+
+	/* Caller should know better */
+	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
+		(out + in > VIRTNET_SEND_COMMAND_SG_MAX));
+
+	out++; /* Add header */
+	in++; /* Add return status */
+
+	ctrl.class = class;
+	ctrl.cmd = cmd;
+
+	sg_init_table(sg, out + in);
+
+	sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
+	for_each_sg(data, s, out + in - 2, i)
+		sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
+	sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
+
+	BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi, GFP_ATOMIC) < 0);
+
+	virtqueue_kick(vi->cvq);
+
+	/* Spin for a response, the kick causes an ioport write, trapping
+	 * into the hypervisor, so the request should be handled immediately.
+	 */
+	while (!virtqueue_get_buf(vi->cvq, &tmp))
+		cpu_relax();
+
+	return status == VIRTIO_NET_OK;
+}
+
 static int virtnet_set_mac_address(struct net_device *dev, void *p)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
 	struct virtio_device *vdev = vi->vdev;
 	int ret;
+	struct sockaddr *addr = p;
+	struct scatterlist sg;
 
-	ret = eth_mac_addr(dev, p);
+	ret = eth_prepare_mac_addr_change(dev, p);
 	if (ret)
 		return ret;
 
-	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
+	if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_MAC_ADDR)) {
+		sg_init_one(&sg, addr->sa_data, dev->addr_len);
+		if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_MAC,
+					  VIRTIO_NET_CTRL_MAC_ADDR_SET,
+					  &sg, 1, 0)) {
+			dev_warn(&vdev->dev,
+				 "Failed to set mac address by vq command.\n");
+			return -EINVAL;
+		}
+	} else if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
 		vdev->config->set(vdev, offsetof(struct virtio_net_config, mac),
-		                  dev->dev_addr, dev->addr_len);
+				  addr->sa_data, dev->addr_len);
+	}
+
+	eth_commit_mac_addr_change(dev, p);
 
 	return 0;
 }
@@ -819,51 +877,6 @@ static void virtnet_netpoll(struct net_device *dev)
 }
 #endif
 
-/*
- * Send command via the control virtqueue and check status.  Commands
- * supported by the hypervisor, as indicated by feature bits, should
- * never fail unless improperly formated.
- */
-static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
-				 struct scatterlist *data, int out, int in)
-{
-	struct scatterlist *s, sg[VIRTNET_SEND_COMMAND_SG_MAX + 2];
-	struct virtio_net_ctrl_hdr ctrl;
-	virtio_net_ctrl_ack status = ~0;
-	unsigned int tmp;
-	int i;
-
-	/* Caller should know better */
-	BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ||
-		(out + in > VIRTNET_SEND_COMMAND_SG_MAX));
-
-	out++; /* Add header */
-	in++; /* Add return status */
-
-	ctrl.class = class;
-	ctrl.cmd = cmd;
-
-	sg_init_table(sg, out + in);
-
-	sg_set_buf(&sg[0], &ctrl, sizeof(ctrl));
-	for_each_sg(data, s, out + in - 2, i)
-		sg_set_buf(&sg[i + 1], sg_virt(s), s->length);
-	sg_set_buf(&sg[out + in - 1], &status, sizeof(status));
-
-	BUG_ON(virtqueue_add_buf(vi->cvq, sg, out, in, vi, GFP_ATOMIC) < 0);
-
-	virtqueue_kick(vi->cvq);
-
-	/*
-	 * Spin for a response, the kick causes an ioport write, trapping
-	 * into the hypervisor, so the request should be handled immediately.
-	 */
-	while (!virtqueue_get_buf(vi->cvq, &tmp))
-		cpu_relax();
-
-	return status == VIRTIO_NET_OK;
-}
-
 static void virtnet_ack_link_announce(struct virtnet_info *vi)
 {
 	rtnl_lock();
@@ -1628,6 +1641,7 @@ static unsigned int features[] = {
 	VIRTIO_NET_F_MRG_RXBUF, VIRTIO_NET_F_STATUS, VIRTIO_NET_F_CTRL_VQ,
 	VIRTIO_NET_F_CTRL_RX, VIRTIO_NET_F_CTRL_VLAN,
 	VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
+	VIRTIO_NET_F_CTRL_MAC_ADDR,
 };
 
 static struct virtio_driver virtio_net_driver = {

include/linux/etherdevice.h

@@ -40,6 +40,8 @@ extern int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh,
 extern void eth_header_cache_update(struct hh_cache *hh,
 				    const struct net_device *dev,
 				    const unsigned char *haddr);
+extern int eth_prepare_mac_addr_change(struct net_device *dev, void *p);
+extern void eth_commit_mac_addr_change(struct net_device *dev, void *p);
 extern int eth_mac_addr(struct net_device *dev, void *p);
 extern int eth_change_mtu(struct net_device *dev, int new_mtu);
 extern int eth_validate_addr(struct net_device *dev);

include/uapi/linux/virtio_net.h

@@ -53,6 +53,7 @@
 					 * network */
 #define VIRTIO_NET_F_MQ	22	/* Device supports Receive Flow
 					 * Steering */
+#define VIRTIO_NET_F_CTRL_MAC_ADDR 23	/* Set MAC address */
 
 #define VIRTIO_NET_S_LINK_UP	1	/* Link is up */
 #define VIRTIO_NET_S_ANNOUNCE	2	/* Announcement is needed */
@@ -127,7 +128,7 @@ typedef __u8 virtio_net_ctrl_ack;
  #define VIRTIO_NET_CTRL_RX_NOBCAST      5
 
 /*
- * Control the MAC filter table.
+ * Control the MAC
  *
  * The MAC filter table is managed by the hypervisor, the guest should
  * assume the size is infinite.  Filtering should be considered
@@ -140,6 +141,10 @@ typedef __u8 virtio_net_ctrl_ack;
  * first sg list contains unicast addresses, the second is for multicast.
  * This functionality is present if the VIRTIO_NET_F_CTRL_RX feature
  * is available.
+ *
+ * The ADDR_SET command requests one out scatterlist, it contains a
+ * 6 bytes MAC address. This functionality is present if the
+ * VIRTIO_NET_F_CTRL_MAC_ADDR feature is available.
  */
 struct virtio_net_ctrl_mac {
 	__u32 entries;
@@ -148,6 +153,7 @@ struct virtio_net_ctrl_mac {
 
 #define VIRTIO_NET_CTRL_MAC    1
  #define VIRTIO_NET_CTRL_MAC_TABLE_SET        0
+ #define VIRTIO_NET_CTRL_MAC_ADDR_SET         1
 
 /*
  * Control VLAN filtering

net/ethernet/eth.c

@@ -271,6 +271,36 @@ void eth_header_cache_update(struct hh_cache *hh,
 }
 EXPORT_SYMBOL(eth_header_cache_update);
 
+/**
+ * eth_prepare_mac_addr_change - prepare for mac change
+ * @dev: network device
+ * @p: socket address
+ */
+int eth_prepare_mac_addr_change(struct net_device *dev, void *p)
+{
+	struct sockaddr *addr = p;
+
+	if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
+		return -EBUSY;
+	if (!is_valid_ether_addr(addr->sa_data))
+		return -EADDRNOTAVAIL;
+	return 0;
+}
+EXPORT_SYMBOL(eth_prepare_mac_addr_change);
+
+/**
+ * eth_commit_mac_addr_change - commit mac change
+ * @dev: network device
+ * @p: socket address
+ */
+void eth_commit_mac_addr_change(struct net_device *dev, void *p)
+{
+	struct sockaddr *addr = p;
+
+	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
+}
+EXPORT_SYMBOL(eth_commit_mac_addr_change);
+
 /**
  * eth_mac_addr - set new Ethernet hardware address
  * @dev: network device
@@ -283,13 +313,12 @@ EXPORT_SYMBOL(eth_header_cache_update);
  */
 int eth_mac_addr(struct net_device *dev, void *p)
 {
-	struct sockaddr *addr = p;
+	int ret;
 
-	if (!(dev->priv_flags & IFF_LIVE_ADDR_CHANGE) && netif_running(dev))
-		return -EBUSY;
-	if (!is_valid_ether_addr(addr->sa_data))
-		return -EADDRNOTAVAIL;
-	memcpy(dev->dev_addr, addr->sa_data, ETH_ALEN);
+	ret = eth_prepare_mac_addr_change(dev, p);
+	if (ret < 0)
+		return ret;
+	eth_commit_mac_addr_change(dev, p);
 	return 0;
 }
 EXPORT_SYMBOL(eth_mac_addr);