[PATCH V3 5/6] vDPA: answer num of queue pairs = 1 to userspace when VIRTIO_NET_F_MQ == 0

[Zhu Lingshan <lingshan.zhu@intel.com>]

If VIRTIO_NET_F_MQ == 0, the virtio device should have one queue pair,
so when userspace querying queue pair numbers, it should return mq=1
than zero.

Function vdpa_dev_net_config_fill() fills the attributions of the
vDPA devices, so that it should call vdpa_dev_net_mq_config_fill()
so the parameter in vdpa_dev_net_mq_config_fill()
should be feature_device than feature_driver for the
vDPA devices themselves

Before this change, when MQ = 0, iproute2 output:
$vdpa dev config show vdpa0
vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false
max_vq_pairs 0 mtu 1500

After applying this commit, when MQ = 0, iproute2 output:
$vdpa dev config show vdpa0
vdpa0: mac 00:e8:ca:11:be:05 link up link_announce false
max_vq_pairs 1 mtu 1500

Fixes: a64917bc2e9b (vdpa: Provide interface to read driver features)
Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
---
 drivers/vdpa/vdpa.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index d76b22b2f7ae..846dd37f3549 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -806,9 +806,10 @@ static int vdpa_dev_net_mq_config_fill(struct vdpa_device *vdev,
 	u16 val_u16;
 
 	if ((features & BIT_ULL(VIRTIO_NET_F_MQ)) == 0)
-		return 0;
+		val_u16 = 1;
+	else
+		val_u16 = __virtio16_to_cpu(true, config->max_virtqueue_pairs);
 
-	val_u16 = le16_to_cpu(config->max_virtqueue_pairs);
 	return nla_put_u16(msg, VDPA_ATTR_DEV_NET_CFG_MAX_VQP, val_u16);
 }
 
@@ -842,7 +843,7 @@ static int vdpa_dev_net_config_fill(struct vdpa_device *vdev, struct sk_buff *ms
 			      VDPA_ATTR_PAD))
 		return -EMSGSIZE;
 
-	return vdpa_dev_net_mq_config_fill(vdev, msg, features_driver, &config);
+	return vdpa_dev_net_mq_config_fill(vdev, msg, features_device, &config);
 }
 
 static int
-- 
2.31.1