Subject: Re: [PATCH] vdpa/mlx5: Setup driver only if VIRTIO_CONFIG_S_DRIVER_OK

From: Jason Wang <[email-masked]>
Date: Mon, 7 Sep 2020 06:53:23 -0400 (EDT)

----- Original Message -----
> If the memory map changes before the driver status is
> VIRTIO_CONFIG_S_DRIVER_OK, don't attempt to create resources because it
> may fail. For example, if the VQ is not ready there is no point in
> creating resources.
> 
> Fixes: 1a86b377aa21 ("vdpa/mlx5: Add VDPA driver for supported mlx5 devices")
> Signed-off-by: Eli Cohen <[email-masked]>
> ---
>  drivers/vdpa/mlx5/net/mlx5_vnet.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> index 9df69d5efe8c..c89cd48a0aab 100644
> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
> @@ -1645,6 +1645,9 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_net
> *ndev, struct vhost_iotlb *
>  	if (err)
>  		goto err_mr;
>  
> +	if (!(ndev->mvdev.status & VIRTIO_CONFIG_S_DRIVER_OK))
> +		return 0;
> +

I'm not sure I get this.

It looks to me if set_map() is called before DRIVER_OK, we won't build
any mapping?

Thanks

>  	restore_channels_info(ndev);
>  	err = setup_driver(ndev);
>  	if (err)
> --
> 2.26.0
> 
>