linux-kernel - Re: [PATCH net-next] net: dsa: b53: Create default VLAN entry explicitly

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Message-ID: <20210611103404.jqyw4q5ux7ao27tc@skbuf>
Date:   Fri, 11 Jun 2021 13:34:04 +0300
From:   Vladimir Oltean <olteanv@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     netdev@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net-next] net: dsa: b53: Create default VLAN entry
 explicitly

On Thu, Jun 10, 2021 at 08:57:32PM -0700, Florian Fainelli wrote:
> In case CONFIG_VLAN_8021Q is not set, there will be no call down to the
> b53 driver to ensure that the default PVID VLAN entry will be configured
> with the appropriate untagged attribute towards the CPU port. We were
> implicitly relying on dsa_slave_vlan_rx_add_vid() to do that for us,
> instead make it explicit.
> 
> Reported-by: Vladimir Oltean <olteanv@...il.com>
> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
> ---
>  drivers/net/dsa/b53/b53_common.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
> index 6e199454e41d..5fd9ed327c1b 100644
> --- a/drivers/net/dsa/b53/b53_common.c
> +++ b/drivers/net/dsa/b53/b53_common.c
> @@ -748,9 +748,20 @@ int b53_configure_vlan(struct dsa_switch *ds)
>  
>  	b53_enable_vlan(dev, -1, dev->vlan_enabled, ds->vlan_filtering);
>  
> -	b53_for_each_port(dev, i)
> +	/* Create an untagged VLAN entry for the default PVID in case
> +	 * CONFIG_VLAN_8021Q is disabled and there are no calls to
> +	 * dsa_slave_vlan_rx_add_vid() to create the default VLAN
> +	 * entry. Do this only when the tagging protocol is not
> +	 * DSA_TAG_PROTO_NONE
> +	 */
> +	b53_for_each_port(dev, i) {
> +		v = &dev->vlans[def_vid];
> +		v->members |= BIT(i);
> +		if (dev->tag_protocol != DSA_TAG_PROTO_NONE)
> +			v->untag = v->members;
>  		b53_write16(dev, B53_VLAN_PAGE,
>  			    B53_VLAN_PORT_DEF_TAG(i), def_vid);
> +	}
>  
>  	/* Upon initial call we have not set-up any VLANs, but upon
>  	 * system resume, we need to restore all VLAN entries.
> -- 
> 2.25.1
> 

So VLAN 0 is by default egress-tagged?
This means that for tag_proto == DSA_TAG_PROTO_NONE, you are
reintroducing the problem fixed by commit d965a5432d4c ("net: dsa: b53:
Ensure the default VID is untagged"), aka untagged packets sent from the
DSA master will land as VID-0-tagged on the wire?

I would expect something like this would yield consistent results
between the b53_configure_vlan and the b53_vlan_add code path, is that
true?

-----------------------------[ cut here ]-----------------------------
diff --git a/drivers/net/dsa/b53/b53_common.c b/drivers/net/dsa/b53/b53_common.c
index 6e199454e41d..03456e019406 100644
--- a/drivers/net/dsa/b53/b53_common.c
+++ b/drivers/net/dsa/b53/b53_common.c
@@ -728,6 +728,13 @@ static u16 b53_default_pvid(struct b53_device *dev)
 		return 0;
 }
 
+static bool b53_vlan_port_needs_forced_tagged(struct dsa_switch *ds, int port)
+{
+	struct b53_device *dev = ds->priv;
+
+	return dev->tag_protocol == DSA_TAG_PROTO_NONE && dsa_is_cpu_port(ds, port);
+}
+
 int b53_configure_vlan(struct dsa_switch *ds)
 {
 	struct b53_device *dev = ds->priv;
@@ -748,6 +755,21 @@ int b53_configure_vlan(struct dsa_switch *ds)
 
 	b53_enable_vlan(dev, -1, dev->vlan_enabled, ds->vlan_filtering);
 
+	/* Create an untagged VLAN entry for the default PVID in case
+	 * CONFIG_VLAN_8021Q is disabled and there are no calls to
+	 * dsa_slave_vlan_rx_add_vid() to create the default VLAN
+	 * entry. Do this only when the tagging protocol is not
+	 * DSA_TAG_PROTO_NONE
+	 */
+	v = &dev->vlans[def_vid];
+
+	b53_for_each_port(dev, i) {
+		v->members |= BIT(i);
+
+		if (!b53_vlan_port_needs_forced_tagged(ds, port))
+			v->untag |= BIT(i);
+	}
+
 	b53_for_each_port(dev, i)
 		b53_write16(dev, B53_VLAN_PAGE,
 			    B53_VLAN_PORT_DEF_TAG(i), def_vid);
@@ -1460,13 +1482,6 @@ static int b53_vlan_prepare(struct dsa_switch *ds, int port,
 	return 0;
 }
 
-static bool b53_vlan_port_needs_forced_tagged(struct dsa_switch *ds, int port)
-{
-	struct b53_device *dev = ds->priv;
-
-	return dev->tag_protocol == DSA_TAG_PROTO_NONE && dsa_is_cpu_port(ds, port);
-}
-
 int b53_vlan_add(struct dsa_switch *ds, int port,
 		 const struct switchdev_obj_port_vlan *vlan,
 		 struct netlink_ext_ack *extack)
-----------------------------[ cut here ]-----------------------------