From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Date: Mon, 7 Nov 2016 09:25:06 +0000 (+0800)
Subject: net/virtio: fix multiple queue enabling
X-Git-Tag: spdx-start~5381
X-Git-Url: http://git.droids-corp.org/?p=dpdk.git;a=commitdiff_plain;h=663c76798f197336c41b4929ba374cdbb6f8073c

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 8a0098acb3..079fd6c897 100644
--- 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;
 	}