Re: [Qemu-devel] [PATCH] net: Mark 'vlan' parameter as deprecated

[Jason Wang <jasowang@redhat.com>]

On 2017年01月24日 17:42, Thomas Huth wrote:
> The 'vlan' parameter is a continuous source of confusion for the users,
> many people mix it up with the more common term VLAN (the link layer
> packet encapsulation), and even if they realize that the QEMU 'vlan' is
> rather some kind of network hub emulation, there is still a high risk
> that they configure their QEMU networking in a wrong way with this
> parameter (e.g. by hooking NICs together, so they get a 'loopback'
> between one and the other NIC).
> Thus at one point in time, we should finally get rid of the 'vlan'
> feature in QEMU. Let's do a first step in this direction by declaring
> the 'vlan' parameter as deprecated and informing the users to use the
> 'netdev' parameter instead.
>
> Signed-off-by: Thomas Huth <thuth@redhat.com>
> ---
>   net/net.c | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/net/net.c b/net/net.c
> index 939fe31..fb7af3a 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -970,6 +970,7 @@ static int net_client_init1(const void *object, bool is_netdev, Error **errp)
>       const Netdev *netdev;
>       const char *name;
>       NetClientState *peer = NULL;
> +    static bool vlan_warned;
>   
>       if (is_netdev) {
>           netdev = object;
> @@ -1050,6 +1051,11 @@ static int net_client_init1(const void *object, bool is_netdev, Error **errp)
>               !opts->u.nic.data->has_netdev) {
>               peer = net_hub_add_port(net->has_vlan ? net->vlan : 0, NULL);
>           }
> +
> +        if (net->has_vlan && !vlan_warned) {
> +            error_report("'vlan' is deprecated. Please use 'netdev' instead.");
> +            vlan_warned = true;
> +        }
>       }
>   
>       if (net_client_init_fun[netdev->type](netdev, name, peer, errp) < 0) {

Looks good, but do really want only warn once? Consider we have monitor 
command e.g "host_net_add".

Thanks