Re: [RFC] rtnetlink: handle multiple vlan tags in set_vf_vlan

[Moshe Shemesh <moshe@mellanox.com>]

On 2/21/2019 7:54 PM, Stephen Hemminger wrote:
> The netlink API for IFLA_VF_VLAN_LIST allows multiple VLAN tags to
> be passed (and the message was validated) but only the first VLAN
> tag was being passed to the device. Change to iterate over each tag received.
> 
> Fixes: 79aab093a0b5 ("net: Update API for VF vlan protocol 802.1ad support")
> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
> ---
>   net/core/rtnetlink.c | 19 ++++++++++---------
>   1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
> index a51cab95ba64..3a9ec988ae21 100644
> --- a/net/core/rtnetlink.c
> +++ b/net/core/rtnetlink.c
> @@ -2207,11 +2207,10 @@ static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
>   	if (tb[IFLA_VF_VLAN_LIST]) {
>   		struct ifla_vf_vlan_info *ivvl[MAX_VLAN_LIST_LEN];
>   		struct nlattr *attr;
> -		int rem, len = 0;
> +		int i, rem, len = 0;
>   
> -		err = -EOPNOTSUPP;
>   		if (!ops->ndo_set_vf_vlan)
> -			return err;
> +			return -EOPNOTSUPP;
>   
>   		nla_for_each_nested(attr, tb[IFLA_VF_VLAN_LIST], rem) {
>   			if (nla_type(attr) != IFLA_VF_VLAN_INFO ||
> @@ -2224,13 +2223,15 @@ static int do_setvfinfo(struct net_device *dev, struct nlattr **tb)
>   
>   			len++;
>   		}
> -		if (len == 0)
> -			return -EINVAL;
>   
> -		err = ops->ndo_set_vf_vlan(dev, ivvl[0]->vf, ivvl[0]->vlan,
> -					   ivvl[0]->qos, ivvl[0]->vlan_proto);
> -		if (err < 0)
> -			return err;
> +		err = -EINVAL; /* empty list error */
> +		for (i = 0; i < len; i++) {
> +			err = ops->ndo_set_vf_vlan(dev, ivvl[i]->vf,
> +						   ivvl[i]->vlan, ivvl[i]->qos,
> +						   ivvl[i]->vlan_proto);

Doing that each vlan will just overwrite the vf vlan configuration set 
by its preceding one.
Note #define MAX_VLAN_LIST_LEN 1
The point here was that I had to add the rtnl interface to set vf vlan 
with option to set vf vlan protocol. While doing that I was asked to add 
option to get a list of vlans from user to support QinQ, so once it will 
be needed there won't be a need to add another rtnl interface.

The driver which will support setting double vlan or more per vf will 
change MAX_VLAN_LIST_LEN and change the ndo function.

> +			if (err < 0)
> +				return err;
> +		}
>   	}
>   
>   	if (tb[IFLA_VF_TX_RATE]) {
>