[PATCH net 5/6] virtio-net: fix the vq coalescing setting for vq resize

[Heng Qi <hengqi@linux.alibaba.com>]

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@nvidia.com>
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index f9a7f6afd099..9888218abab4 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;
+			/* Save parameters */
+			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;
+			/* Save parameters */
+			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;
 		}
 	}
 
-- 
2.19.1.6.gb485710b