net/virtio: fix multiple queue enabling

When queue number shrinks to 1 from X, the following code stops us
sending the multiple queue ctrl message:

        if (nb_queues > 1) {
                if (virtio_set_multiple_queues(dev, nb_queues) != 0)
                        return -EINVAL;
        }

This ends up with still X queues being enabled, which is obviously
wrong. Fix it by replacing the check with a multiple queue enabled
or not check.

Fixes: 823ad647950a ("virtio: support multiple queues")

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c
index 8a0098a..079fd6c 100644 (file)
--- a/drivers/net/virtio/virtio_ethdev.c
+++ b/drivers/net/virtio/virtio_ethdev.c
@@ -1472,6 +1472,7 @@ virtio_dev_start(struct rte_eth_dev *dev)
        uint16_t nb_queues, i;
        struct virtnet_rx *rxvq;
        struct virtnet_tx *txvq __rte_unused;
+       struct virtio_hw *hw = dev->data->dev_private;
 
        /* check if lsc interrupt feature is enabled */
        if (dev->data->dev_conf.intr_conf.lsc) {
@@ -1494,7 +1495,7 @@ virtio_dev_start(struct rte_eth_dev *dev)
         *vhost backend will have no chance to be waked up
         */
        nb_queues = RTE_MAX(dev->data->nb_rx_queues, dev->data->nb_tx_queues);
-       if (nb_queues > 1) {
+       if (hw->max_queue_pairs > 1) {
                if (virtio_set_multiple_queues(dev, nb_queues) != 0)
                        return -EINVAL;
        }