netdev - Re: [PATCH net-next 5/6] net: dsa: program VLAN on CPU port from slave

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Message-ID: <CA+h21hofEiB+rypFKrt0Dy3OfUvk5n6s=sTmb9r83yBzVVA7ZQ@mail.gmail.com>
Date:   Fri, 23 Aug 2019 18:44:52 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     Vivien Didelot <vivien.didelot@...il.com>
Cc:     netdev <netdev@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>
Subject: Re: [PATCH net-next 5/6] net: dsa: program VLAN on CPU port from slave

On Thu, 22 Aug 2019 at 23:13, Vivien Didelot <vivien.didelot@...il.com> wrote:
>
> DSA currently programs a VLAN on the CPU port implicitly after the
> related notifier is received by a switch.
>
> While we still need to do this transparent programmation of the DSA
> links in the fabric, programming the CPU port this way may cause
> problems in some corners such as the tag_8021q driver.
>
> Because the dedicated CPU port is specific to a slave, make their
> programmation explicit a few layers up, in the slave code.
>
> Note that technically, DSA links have a dedicated CPU port as well,
> but since they are only used as conduit between interconnected switches
> of a fabric, programming them transparently this way is fine.
>
> Signed-off-by: Vivien Didelot <vivien.didelot@...il.com>
> ---
>  net/dsa/slave.c  | 14 ++++++++++++++
>  net/dsa/switch.c |  5 ++++-
>  2 files changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/net/dsa/slave.c b/net/dsa/slave.c
> index 82e48d247b81..8267c156a51a 100644
> --- a/net/dsa/slave.c
> +++ b/net/dsa/slave.c
> @@ -332,6 +332,10 @@ static int dsa_slave_vlan_add(struct net_device *dev,
>         if (err)
>                 return err;
>
> +       err = dsa_port_vlan_add(dp->cpu_dp, &vlan, trans);
> +       if (err)
> +               return err;
> +
>         return 0;
>  }
>
> @@ -383,6 +387,9 @@ static int dsa_slave_vlan_del(struct net_device *dev,
>         if (dp->bridge_dev && !br_vlan_enabled(dp->bridge_dev))
>                 return 0;
>
> +       /* Do not deprogram the CPU port as it may be shared with other user
> +        * ports which can be members of this VLAN as well.
> +        */

+1 for the comments, the deletion of dp->cpu_dp is less likely to get
patched into the code in the future now.

>         return dsa_port_vlan_del(dp, SWITCHDEV_OBJ_PORT_VLAN(obj));
>  }
>
> @@ -1121,6 +1128,10 @@ static int dsa_slave_vlan_rx_add_vid(struct net_device *dev, __be16 proto,
>         if (ret && ret != -EOPNOTSUPP)
>                 return ret;
>
> +       ret = dsa_port_vid_add(dp->cpu_dp, vid, 0);
> +       if (ret && ret != -EOPNOTSUPP)
> +               return ret;
> +

I think it's worth understanding what the EOPNOTSUPP -> 0 is avoiding.

>         return 0;
>  }
>
> @@ -1151,6 +1162,9 @@ static int dsa_slave_vlan_rx_kill_vid(struct net_device *dev, __be16 proto,
>         if (ret == -EOPNOTSUPP)
>                 ret = 0;
>
> +       /* Do not deprogram the CPU port as it may be shared with other user
> +        * ports which can be members of this VLAN as well.
> +        */
>         return ret;
>  }
>
> diff --git a/net/dsa/switch.c b/net/dsa/switch.c
> index 489eb7b430a4..6a9607518823 100644
> --- a/net/dsa/switch.c
> +++ b/net/dsa/switch.c
> @@ -232,7 +232,7 @@ static bool dsa_switch_vlan_match(struct dsa_switch *ds, int port,
>         if (ds->index == info->sw_index && port == info->port)
>                 return true;
>
> -       if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
> +       if (dsa_is_dsa_port(ds, port))

Much better, thank you.



>                 return true;
>
>         return false;
> @@ -288,6 +288,9 @@ static int dsa_switch_vlan_del(struct dsa_switch *ds,
>         if (ds->index == info->sw_index)
>                 return ds->ops->port_vlan_del(ds, info->port, info->vlan);
>
> +       /* Do not deprogram the DSA links as they may be used as conduit
> +        * for other VLAN members in the fabric.
> +        */
>         return 0;
>  }
>
> --
> 2.23.0
>