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

[Thomas Huth]

On 25.01.2017 08:50, Jason Wang wrote:
> 
> 
> 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 <address@hidden>
>> ---
>>   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".

I don't mind ... I can remove the "vlan_warned" check, but then you'll
get a lot of error messages at once if you start QEMU with multiple
"-net" parameters that use "vlan=...". Is that ok for you? If yes, I'll
send an updated v2 of my patch without that "vlan_warned" check.

 Thomas