On Wed, May 24, 2023 at 5:15 PM Michael S. Tsirkin [off-list ref] wrote:

On Wed, May 24, 2023 at 04:18:41PM +0800, Jason Wang wrote:

quoted

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 <redacted>
---
Changes since V1:
- use RTNL to synchronize rx mode worker
---
 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 56ca1d270304..5d2f1da4eaa0 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -265,6 +265,12 @@ struct virtnet_info {
      /* Work struct for config space updates */
      struct work_struct config_work;

+     /* Work struct for config rx mode */

With a bit less abbreviation maybe? setting rx mode?

That's fine.

quoted

+     struct work_struct rx_mode_work;
+
+     /* Is rx mode work enabled? */

Ugh not a great comment.

Any suggestions for this. E.g we had:

        /* Is delayed refill enabled? */

quoted

+     bool rx_mode_work_enabled;
+

quoted

      /* Does the affinity hint is set for virtqueues? */
      bool affinity_hint_set;

@@ -388,6 +394,20 @@ 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)
 {

@@ -2341,9 +2361,11 @@ 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;

@@ -2356,6 +2378,8 @@ 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);

@@ -2373,14 +2397,19 @@ 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);

@@ -2401,6 +2430,8 @@ 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));

@@ -2408,9 +2439,19 @@ 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);
+}
+

quoted

 static int virtnet_vlan_rx_add_vid(struct net_device *dev,
                                 __be16 proto, u16 vid)
 {

@@ -3181,6 +3222,8 @@ 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);

Hmm so queued rx mode work will just get skipped
and on restore we get a wrong rx mode.
Any way to make this more robust?

It could be done by scheduling a work on restore.

Thanks

quoted

@@ -3203,6 +3246,7 @@ 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);

@@ -4002,6 +4046,7 @@ 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)) {

@@ -4110,6 +4155,8 @@ 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();

@@ -4207,6 +4254,8 @@ 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);

--

2.25.1