[PATCH] net/virtio-user: fix number of vrings calculation

[Maxime Coquelin]

On 2/10/23 16:10, Maxime Coquelin wrote:
> When moving to dynamic allocation of vrings metadata, the
> number of vrings to allocate was incremented if the backend
> supports control queue.
> 
> The problem is that the control queue metadata have to be
> allocated even if the backend does not use it directly,
> since the control queue is managed by the Virtio-user layer
> as soon as multiqueue is negotiated..
> 
> This patch fixes this by incrementing the number of vrings
> as soon as the device features have VIRTIO_NET_F_MQ.
> 
> Fixes: d57c3a601e44 ("net/virtio-user: remove max queues limitation")
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
> ---
> 
> I plan to squash it with faulty commit in the Virtio branch
> since it has not been pulled yet by Thomas once acked and
> if no objection.
> 
>   drivers/net/virtio/virtio_user/virtio_user_dev.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index cf58b63029..ccb4d7326b 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -575,7 +575,7 @@ virtio_user_alloc_vrings(struct virtio_user_dev *dev)
>   	bool packed_ring = !!(dev->device_features & (1ull << VIRTIO_F_RING_PACKED));
>   
>   	nr_vrings = dev->max_queue_pairs * 2;
> -	if (dev->hw_cvq)
> +	if (dev->device_features & (1ull << VIRTIO_NET_F_MQ))
>   		nr_vrings++;
>   
>   	dev->callfds = rte_zmalloc("virtio_user_dev", nr_vrings * sizeof(*dev->callfds), 0);

Squashed with d57c3a601e44 and pushed to next-virtio.

Thanks,
Maxime