net: dsa: sja1105: delete the best_effort_vlan_filtering mode

Simply put, the best-effort VLAN filtering mode relied on VLAN retagging
from a bridge VLAN towards a tag_8021q sub-VLAN in order to be able to
decode the source port in the tagger, but the VLAN retagging
implementation inside the sja1105 chips is not the best and we were
relying on marginal operating conditions.

The most notable limitation of the best-effort VLAN filtering mode is
its incapacity to treat this case properly:

ip link add br0 type bridge vlan_filtering 1
ip link set swp2 master br0
ip link set swp4 master br0
bridge vlan del dev swp4 vid 1
bridge vlan add dev swp4 vid 1 pvid

When sending an untagged packet through swp2, the expectation is for it
to be forwarded to swp4 as egress-tagged (so it will contain VLAN ID 1
on egress). But the switch will send it as egress-untagged.

There was an attempt to fix this here:
https://patchwork.kernel.org/project/netdevbpf/patch/20210407201452.1703261-2-olteanv@gmail.com/

but it failed miserably because it broke PTP RX timestamping, in a way
that cannot be corrected due to hardware issues related to VLAN
retagging.

So with either PTP broken or pushing VLAN headers on egress for untagged
packets being broken, the sad reality is that the best-effort VLAN
filtering code is broken. Delete it.

Note that this means there will be a temporary loss of functionality in
this driver until it is replaced with something better (network stack
RX/TX capability for "mode 2" as described in
Documentation/networking/dsa/sja1105.rst, the "port under VLAN-aware
bridge" case). We simply cannot keep this code until that driver rework
is done, it is super bloated and tangled with tag_8021q.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 113 deletions

diff --git a/drivers/net/dsa/sja1105/sja1105_devlink.c b/drivers/net/dsa/sja1105/sja1105_devlink.c
index b6a4a16b8c7e..05c7f4ca3b1a 100644
--- a/drivers/net/dsa/sja1105/sja1105_devlink.c
+++ b/drivers/net/dsa/sja1105/sja1105_devlink.c
@@ -115,105 +115,6 @@ static void sja1105_teardown_devlink_regions(struct dsa_switch *ds)
 	kfree(priv->regions);
 }
 
-static int sja1105_best_effort_vlan_filtering_get(struct sja1105_private *priv,
-						  bool *be_vlan)
-{
-	*be_vlan = priv->best_effort_vlan_filtering;
-
-	return 0;
-}
-
-static int sja1105_best_effort_vlan_filtering_set(struct sja1105_private *priv,
-						  bool be_vlan)
-{
-	struct dsa_switch *ds = priv->ds;
-	bool vlan_filtering;
-	int port;
-	int rc;
-
-	priv->best_effort_vlan_filtering = be_vlan;
-
-	rtnl_lock();
-	for (port = 0; port < ds->num_ports; port++) {
-		struct dsa_port *dp;
-
-		if (!dsa_is_user_port(ds, port))
-			continue;
-
-		dp = dsa_to_port(ds, port);
-		vlan_filtering = dsa_port_is_vlan_filtering(dp);
-
-		rc = sja1105_vlan_filtering(ds, port, vlan_filtering, NULL);
-		if (rc)
-			break;
-	}
-	rtnl_unlock();
-
-	return rc;
-}
-
-enum sja1105_devlink_param_id {
-	SJA1105_DEVLINK_PARAM_ID_BASE = DEVLINK_PARAM_GENERIC_ID_MAX,
-	SJA1105_DEVLINK_PARAM_ID_BEST_EFFORT_VLAN_FILTERING,
-};
-
-int sja1105_devlink_param_get(struct dsa_switch *ds, u32 id,
-			      struct devlink_param_gset_ctx *ctx)
-{
-	struct sja1105_private *priv = ds->priv;
-	int err;
-
-	switch (id) {
-	case SJA1105_DEVLINK_PARAM_ID_BEST_EFFORT_VLAN_FILTERING:
-		err = sja1105_best_effort_vlan_filtering_get(priv,
-							     &ctx->val.vbool);
-		break;
-	default:
-		err = -EOPNOTSUPP;
-		break;
-	}
-
-	return err;
-}
-
-int sja1105_devlink_param_set(struct dsa_switch *ds, u32 id,
-			      struct devlink_param_gset_ctx *ctx)
-{
-	struct sja1105_private *priv = ds->priv;
-	int err;
-
-	switch (id) {
-	case SJA1105_DEVLINK_PARAM_ID_BEST_EFFORT_VLAN_FILTERING:
-		err = sja1105_best_effort_vlan_filtering_set(priv,
-							     ctx->val.vbool);
-		break;
-	default:
-		err = -EOPNOTSUPP;
-		break;
-	}
-
-	return err;
-}
-
-static const struct devlink_param sja1105_devlink_params[] = {
-	DSA_DEVLINK_PARAM_DRIVER(SJA1105_DEVLINK_PARAM_ID_BEST_EFFORT_VLAN_FILTERING,
-				 "best_effort_vlan_filtering",
-				 DEVLINK_PARAM_TYPE_BOOL,
-				 BIT(DEVLINK_PARAM_CMODE_RUNTIME)),
-};
-
-static int sja1105_setup_devlink_params(struct dsa_switch *ds)
-{
-	return dsa_devlink_params_register(ds, sja1105_devlink_params,
-					   ARRAY_SIZE(sja1105_devlink_params));
-}
-
-static void sja1105_teardown_devlink_params(struct dsa_switch *ds)
-{
-	dsa_devlink_params_unregister(ds, sja1105_devlink_params,
-				      ARRAY_SIZE(sja1105_devlink_params));
-}
-
 int sja1105_devlink_info_get(struct dsa_switch *ds,
 			     struct devlink_info_req *req,
 			     struct netlink_ext_ack *extack)
@@ -233,23 +134,10 @@ int sja1105_devlink_info_get(struct dsa_switch *ds,
 
 int sja1105_devlink_setup(struct dsa_switch *ds)
 {
-	int rc;
-
-	rc = sja1105_setup_devlink_params(ds);
-	if (rc)
-		return rc;
-
-	rc = sja1105_setup_devlink_regions(ds);
-	if (rc < 0) {
-		sja1105_teardown_devlink_params(ds);
-		return rc;
-	}
-
-	return 0;
+	return sja1105_setup_devlink_regions(ds);
 }
 
 void sja1105_devlink_teardown(struct dsa_switch *ds)
 {
-	sja1105_teardown_devlink_params(ds);
 	sja1105_teardown_devlink_regions(ds);
 }