[PATCH net-next v4 1/2] virtio-net: convert rx mode setting to use workqueue

[Jason Wang]

This patch convert rx mode setting to be done in a workqueue, this is
a must for allow to sleep when waiting for the cvq command to
response since current code is executed under addr spin lock.

Note that we need to disable and flush the workqueue during freeze,
this means the rx mode setting is lost after resuming. This is not the
bug of this patch as we never try to restore rx mode setting during
resume.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
 drivers/net/virtio_net.c | 55 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d67b36fdba0d..9f3b1d6ac33d 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -274,6 +274,12 @@ struct virtnet_info {
 	/* Work struct for config space updates */
 	struct work_struct config_work;
 
+	/* Work struct for setting rx mode */
+	struct work_struct rx_mode_work;
+
+	/* OK to queue work setting RX mode? */
+	bool rx_mode_work_enabled;
+
 	/* Does the affinity hint is set for virtqueues? */
 	bool affinity_hint_set;
 
@@ -397,6 +403,20 @@ static void disable_delayed_refill(struct virtnet_info *vi)
 	spin_unlock_bh(&vi->refill_lock);
 }
 
+static void enable_rx_mode_work(struct virtnet_info *vi)
+{
+	rtnl_lock();
+	vi->rx_mode_work_enabled = true;
+	rtnl_unlock();
+}
+
+static void disable_rx_mode_work(struct virtnet_info *vi)
+{
+	rtnl_lock();
+	vi->rx_mode_work_enabled = false;
+	rtnl_unlock();
+}
+
 static void virtqueue_napi_schedule(struct napi_struct *napi,
 				    struct virtqueue *vq)
 {
@@ -2448,9 +2468,11 @@ static int virtnet_close(struct net_device *dev)
 	return 0;
 }
 
-static void virtnet_set_rx_mode(struct net_device *dev)
+static void virtnet_rx_mode_work(struct work_struct *work)
 {
-	struct virtnet_info *vi = netdev_priv(dev);
+	struct virtnet_info *vi =
+		container_of(work, struct virtnet_info, rx_mode_work);
+	struct net_device *dev = vi->dev;
 	struct scatterlist sg[2];
 	struct virtio_net_ctrl_mac *mac_data;
 	struct netdev_hw_addr *ha;
@@ -2463,6 +2485,8 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 		return;
 
+	rtnl_lock();
+
 	vi->ctrl->promisc = ((dev->flags & IFF_PROMISC) != 0);
 	vi->ctrl->allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 
@@ -2480,14 +2504,19 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 		dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
 			 vi->ctrl->allmulti ? "en" : "dis");
 
+	netif_addr_lock_bh(dev);
+
 	uc_count = netdev_uc_count(dev);
 	mc_count = netdev_mc_count(dev);
 	/* MAC filter - use one buffer for both lists */
 	buf = kzalloc(((uc_count + mc_count) * ETH_ALEN) +
 		      (2 * sizeof(mac_data->entries)), GFP_ATOMIC);
 	mac_data = buf;
-	if (!buf)
+	if (!buf) {
+		netif_addr_unlock_bh(dev);
+		rtnl_unlock();
 		return;
+	}
 
 	sg_init_table(sg, 2);
 
@@ -2508,6 +2537,8 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 	netdev_for_each_mc_addr(ha, dev)
 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
 
+	netif_addr_unlock_bh(dev);
+
 	sg_set_buf(&sg[1], mac_data,
 		   sizeof(mac_data->entries) + (mc_count * ETH_ALEN));
 
@@ -2515,9 +2546,19 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 				  VIRTIO_NET_CTRL_MAC_TABLE_SET, sg))
 		dev_warn(&dev->dev, "Failed to set MAC filter table.\n");
 
+	rtnl_unlock();
+
 	kfree(buf);
 }
 
+static void virtnet_set_rx_mode(struct net_device *dev)
+{
+	struct virtnet_info *vi = netdev_priv(dev);
+
+	if (vi->rx_mode_work_enabled)
+		schedule_work(&vi->rx_mode_work);
+}
+
 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
 				   __be16 proto, u16 vid)
 {
@@ -3286,6 +3327,8 @@ static void virtnet_freeze_down(struct virtio_device *vdev)
 
 	/* Make sure no work handler is accessing the device */
 	flush_work(&vi->config_work);
+	disable_rx_mode_work(vi);
+	flush_work(&vi->rx_mode_work);
 
 	netif_tx_lock_bh(vi->dev);
 	netif_device_detach(vi->dev);
@@ -3308,6 +3351,7 @@ static int virtnet_restore_up(struct virtio_device *vdev)
 	virtio_device_ready(vdev);
 
 	enable_delayed_refill(vi);
+	enable_rx_mode_work(vi);
 
 	if (netif_running(vi->dev)) {
 		err = virtnet_open(vi->dev);
@@ -4121,6 +4165,7 @@ static int virtnet_probe(struct virtio_device *vdev)
 	vdev->priv = vi;
 
 	INIT_WORK(&vi->config_work, virtnet_config_changed_work);
+	INIT_WORK(&vi->rx_mode_work, virtnet_rx_mode_work);
 	spin_lock_init(&vi->refill_lock);
 
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) {
@@ -4229,6 +4274,8 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (vi->has_rss || vi->has_rss_hash_report)
 		virtnet_init_default_rss(vi);
 
+	enable_rx_mode_work(vi);
+
 	/* serialize netdev register + virtio_device_ready() with ndo_open() */
 	rtnl_lock();
 
@@ -4326,6 +4373,8 @@ static void virtnet_remove(struct virtio_device *vdev)
 
 	/* Make sure no work handler is accessing the device. */
 	flush_work(&vi->config_work);
+	disable_rx_mode_work(vi);
+	flush_work(&vi->rx_mode_work);
 
 	unregister_netdev(vi->dev);
 
-- 
2.39.3