netdev - Re: [PATCH] net: dsa: mv88e6xxx: rework in-chip bridging

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Message-ID: <ab86ad59-06af-b4ab-0bc6-dace73f04ef0@linux-m68k.org>
Date:   Wed, 4 Oct 2017 16:20:12 +1000
From:   Greg Ungerer <gerg@...ux-m68k.org>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>
Subject: Re: [PATCH] net: dsa: mv88e6xxx: rework in-chip bridging

Hi Vivien,

On Wed, Mar 29, 2017 at 04:30:16PM -0400, Vivien Didelot wrote:
> All ports -- internal and external, for chips featuring a PVT -- have a
> mask restricting to which internal ports a frame is allowed to egress.
> 
> Now that DSA exposes the number of ports and their bridge devices, it is
> possible to extract the code generating the VLAN map and make it generic
> so that it can be shared later with the cross-chip bridging code.

This patch changes the behavior of interfaces on startup if they are
not part of a bridge.

I have a board with a Marvell 6350 switch with a device tree that sets
up the 5 ports as lan1, lan2, lan3, lan4, wan. With kernels before
this patch (so linux-4.12 and older) after system startup I could do:

  ifconfig lan1 192.168.0.1

And then ping out that interface with no problems.

After this patch is applied (effects linux-4.13 and newer) then the
ping fails:

  PING 192.168.0.22 (192.168.0.22) 56(84) bytes of data.
  From 192.168.0.1 icmp_seq=1 Destination Host Unreachable
  From 192.168.0.1 icmp_seq=2 Destination Host Unreachable
  From 192.168.0.1 icmp_seq=3 Destination Host Unreachable

If I incorporate an interface into a bridge then it all works ok.
So simply:

  brctl addbr br0
  brctl addif br0 lan1
  ifconfig lan1 up
  ifconfig br0 192.168.0.1

Then pings out work as expected. And if I now remove that lan1
interface from the bridge and use it alone again then it will
now work ok:

  ifconfig br0 down
  brctl delif br0 lan1
  ifconfig lan1 192.168.0.1

And that now pings ok.

I fixed this with the attached patch. It is probably not the correct
approach, but it does restore the older behavior.

What do you think?

Regards
Greg



> Signed-off-by: Vivien Didelot <vivien.dide...@...oirfairelinux.com>
> ---
>  drivers/net/dsa/mv88e6xxx/chip.c | 53 ++++++++++++++++++++++++++--------------
>  1 file changed, 34 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
> index b114bf8e6a11..e5165831e8b5 100644
> --- a/drivers/net/dsa/mv88e6xxx/chip.c
> +++ b/drivers/net/dsa/mv88e6xxx/chip.c
> @@ -1123,27 +1123,42 @@ static int mv88e6xxx_set_eee(struct dsa_switch *ds, int 
> port,
>         return err;
>  }
>  
> +static u16 mv88e6xxx_port_vlan(struct mv88e6xxx_chip *chip, int dev, int port)
> +{
> +       struct dsa_switch *ds = NULL;
> +       struct net_device *br;
> +       u16 pvlan;
> +       int i;
> +
> +       if (dev < DSA_MAX_SWITCHES)
> +               ds = chip->ds->dst->ds[dev];
> +
> +       /* Prevent frames from unknown switch or port */
> +       if (!ds || port >= ds->num_ports)
> +               return 0;
> +
> +       /* Frames from DSA links and CPU ports can egress any local port */
> +       if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port))
> +               return mv88e6xxx_port_mask(chip);
> +
> +       br = ds->ports[port].bridge_dev;
> +       pvlan = 0;
> +
> +       /* Frames from user ports can egress any local DSA links and CPU ports,
> +        * as well as any local member of their bridge group.
> +        */
> +       for (i = 0; i < mv88e6xxx_num_ports(chip); ++i)
> +               if (dsa_is_cpu_port(chip->ds, i) ||
> +                   dsa_is_dsa_port(chip->ds, i) ||
> +                   (br && chip->ds->ports[i].bridge_dev == br))
> +                       pvlan |= BIT(i);
> +
> +       return pvlan;
> +}
> +
>  static int _mv88e6xxx_port_based_vlan_map(struct mv88e6xxx_chip *chip, int 
> port)
>  {
> -       struct dsa_switch *ds = chip->ds;
> -       struct net_device *bridge = ds->ports[port].bridge_dev;
> -       u16 output_ports = 0;
> -       int i;
> -
> -       /* allow CPU port or DSA link(s) to send frames to every port */
> -       if (dsa_is_cpu_port(ds, port) || dsa_is_dsa_port(ds, port)) {
> -               output_ports = ~0;
> -       } else {
> -               for (i = 0; i < mv88e6xxx_num_ports(chip); ++i) {
> -                       /* allow sending frames to every group member */
> -                       if (bridge && ds->ports[i].bridge_dev == bridge)
> -                               output_ports |= BIT(i);
> -
> -                       /* allow sending frames to CPU port and DSA link(s) */
> -                       if (dsa_is_cpu_port(ds, i) || dsa_is_dsa_port(ds, i))
> -                               output_ports |= BIT(i);
> -               }
> -       }
> +       u16 output_ports = mv88e6xxx_port_vlan(chip, chip->ds->index, port);
>  
>         /* prevent frames from going back out of the port they came in on */
>         output_ports &= ~BIT(port);
> -- 


View attachment "0001-linux-dsa-fix-first-use-port-breakage.patch" of type "text/x-patch" (1546 bytes)