Patch "virtio-net: fix the vq coalescing setting for vq resize" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    virtio-net: fix the vq coalescing setting for vq resize

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     virtio-net-fix-the-vq-coalescing-setting-for-vq-resi.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6d15a71f407dec481732ab287daaaa92e79f301d
Author: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>
Date:   Sun Oct 8 14:27:43 2023 +0800

    virtio-net: fix the vq coalescing setting for vq resize
    
    [ Upstream commit f61fe5f081cf40de08d0a4c89659baf23c900f0c ]
    
    According to the definition of virtqueue coalescing spec[1]:
    
      Upon disabling and re-enabling a transmit virtqueue, the device MUST set
      the coalescing parameters of the virtqueue to those configured through the
      VIRTIO_NET_CTRL_NOTF_COAL_TX_SET command, or, if the driver did not set
      any TX coalescing parameters, to 0.
    
      Upon disabling and re-enabling a receive virtqueue, the device MUST set
      the coalescing parameters of the virtqueue to those configured through the
      VIRTIO_NET_CTRL_NOTF_COAL_RX_SET command, or, if the driver did not set
      any RX coalescing parameters, to 0.
    
    We need to add this setting for vq resize (ethtool -G) where vq_reset happens.
    
    [1] https://lists.oasis-open.org/archives/virtio-dev/202303/msg00415.html
    
    Fixes: 394bd87764b6 ("virtio_net: support per queue interrupt coalesce command")
    Cc: Gavin Li <gavinl@xxxxxxxxxx>
    Signed-off-by: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>
    Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 4211f28c59dc8..cd1e9e87eaa35 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2855,6 +2855,9 @@ static void virtnet_get_ringparam(struct net_device *dev,
 	ring->tx_pending = virtqueue_get_vring_size(vi->sq[0].vq);
 }
 
+static int virtnet_send_ctrl_coal_vq_cmd(struct virtnet_info *vi,
+					 u16 vqn, u32 max_usecs, u32 max_packets);
+
 static int virtnet_set_ringparam(struct net_device *dev,
 				 struct ethtool_ringparam *ring,
 				 struct kernel_ethtool_ringparam *kernel_ring,
@@ -2890,12 +2893,36 @@ static int virtnet_set_ringparam(struct net_device *dev,
 			err = virtnet_tx_resize(vi, sq, ring->tx_pending);
 			if (err)
 				return err;
+
+			/* Upon disabling and re-enabling a transmit virtqueue, the device must
+			 * set the coalescing parameters of the virtqueue to those configured
+			 * through the VIRTIO_NET_CTRL_NOTF_COAL_TX_SET command, or, if the driver
+			 * did not set any TX coalescing parameters, to 0.
+			 */
+			err = virtnet_send_ctrl_coal_vq_cmd(vi, txq2vq(i),
+							    vi->intr_coal_tx.max_usecs,
+							    vi->intr_coal_tx.max_packets);
+			if (err)
+				return err;
+
+			vi->sq[i].intr_coal.max_usecs = vi->intr_coal_tx.max_usecs;
+			vi->sq[i].intr_coal.max_packets = vi->intr_coal_tx.max_packets;
 		}
 
 		if (ring->rx_pending != rx_pending) {
 			err = virtnet_rx_resize(vi, rq, ring->rx_pending);
 			if (err)
 				return err;
+
+			/* The reason is same as the transmit virtqueue reset */
+			err = virtnet_send_ctrl_coal_vq_cmd(vi, rxq2vq(i),
+							    vi->intr_coal_rx.max_usecs,
+							    vi->intr_coal_rx.max_packets);
+			if (err)
+				return err;
+
+			vi->rq[i].intr_coal.max_usecs = vi->intr_coal_rx.max_usecs;
+			vi->rq[i].intr_coal.max_packets = vi->intr_coal_rx.max_packets;
 		}
 	}