[RFC PATCH 1/4] virtio-net: convert rx mode setting to use workqueue

[Jason Wang <jasowang@xxxxxxxxxx>]

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.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
 drivers/net/virtio_net.c | 64 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 61 insertions(+), 3 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 86e52454b5b5..8225496ccb1e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -260,6 +260,15 @@ struct virtnet_info {
 	/* Work struct for config space updates */
 	struct work_struct config_work;
 
+	/* Work struct for config rx mode */
+	struct work_struct rx_mode_work;
+
+	/* Is rx_mode_work enabled? */
+	bool rx_mode_work_enabled;
+
+	/* The lock to synchronize the access to refill_enabled */
+	spinlock_t rx_mode_lock;
+
 	/* Does the affinity hint is set for virtqueues? */
 	bool affinity_hint_set;
 
@@ -383,6 +392,22 @@ 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)
+{
+	spin_lock_bh(&vi->rx_mode_lock);
+	vi->rx_mode_work_enabled = true;
+	spin_unlock_bh(&vi->rx_mode_lock);
+}
+
+static void disable_rx_mode_work(struct virtnet_info *vi)
+{
+	spin_lock_bh(&vi->rx_mode_lock);
+	vi->rx_mode_work_enabled = false;
+	spin_unlock_bh(&vi->rx_mode_lock);
+
+	flush_work(&vi->rx_mode_work);
+}
+
 static void virtqueue_napi_schedule(struct napi_struct *napi,
 				    struct virtqueue *vq)
 {
@@ -2160,9 +2185,11 @@ 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;
@@ -2175,8 +2202,12 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 	if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
 		return;
 
+	rtnl_lock();
+
+	netif_addr_lock_bh(dev);
 	vi->ctrl->promisc = ((dev->flags & IFF_PROMISC) != 0);
 	vi->ctrl->allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
+	netif_addr_unlock_bh(dev);
 
 	sg_init_one(sg, &vi->ctrl->promisc, sizeof(vi->ctrl->promisc));
 
@@ -2192,14 +2223,19 @@ 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);
 
@@ -2220,6 +2256,8 @@ 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));
 
@@ -2227,9 +2265,21 @@ 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);
+
+	spin_lock(&vi->rx_mode_lock);
+	if (vi->rx_mode_work_enabled)
+		schedule_work(&vi->rx_mode_work);
+	spin_unlock(&vi->rx_mode_lock);
+}
+
 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
 				   __be16 proto, u16 vid)
 {
@@ -3000,6 +3050,7 @@ 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);
 
 	netif_tx_lock_bh(vi->dev);
 	netif_device_detach(vi->dev);
@@ -3022,6 +3073,8 @@ static int virtnet_restore_up(struct virtio_device *vdev)
 	virtio_device_ready(vdev);
 
 	enable_delayed_refill(vi);
+	enable_rx_mode_work(vi);
+	virtnet_set_rx_mode(vi->dev);
 
 	if (netif_running(vi->dev)) {
 		err = virtnet_open(vi->dev);
@@ -3799,7 +3852,9 @@ 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);
+	spin_lock_init(&vi->rx_mode_lock);
 
 	if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
 		vi->mergeable_rx_bufs = true;
@@ -3905,6 +3960,8 @@ 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();
 
@@ -3984,6 +4041,7 @@ 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);
 
 	unregister_netdev(vi->dev);
 
-- 
2.25.1

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