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, 12 deletions

diff --git a/drivers/net/dsa/sja1105/sja1105.h b/drivers/net/dsa/sja1105/sja1105.h
index 221c7abdef0e..869b19c08fc0 100644
--- a/drivers/net/dsa/sja1105/sja1105.h
+++ b/drivers/net/dsa/sja1105/sja1105.h
@@ -234,19 +234,13 @@ struct sja1105_bridge_vlan {
 	bool untagged;
 };
 
-enum sja1105_vlan_state {
-	SJA1105_VLAN_UNAWARE,
-	SJA1105_VLAN_BEST_EFFORT,
-	SJA1105_VLAN_FILTERING_FULL,
-};
-
 struct sja1105_private {
 	struct sja1105_static_config static_config;
 	bool rgmii_rx_delay[SJA1105_MAX_NUM_PORTS];
 	bool rgmii_tx_delay[SJA1105_MAX_NUM_PORTS];
 	phy_interface_t phy_mode[SJA1105_MAX_NUM_PORTS];
 	bool fixed_link[SJA1105_MAX_NUM_PORTS];
-	bool best_effort_vlan_filtering;
+	bool vlan_aware;
 	unsigned long learn_ena;
 	unsigned long ucast_egress_floods;
 	unsigned long bcast_egress_floods;
@@ -264,7 +258,6 @@ struct sja1105_private {
 	 */
 	struct mutex mgmt_lock;
 	struct dsa_8021q_context *dsa_8021q_ctx;
-	enum sja1105_vlan_state vlan_state;
 	struct devlink_region **regions;
 	struct sja1105_cbs_entry *cbs;
 	struct mii_bus *mdio_base_t1;
@@ -311,10 +304,6 @@ int sja1110_pcs_mdio_write(struct mii_bus *bus, int phy, int reg, u16 val);
 /* From sja1105_devlink.c */
 int sja1105_devlink_setup(struct dsa_switch *ds);
 void sja1105_devlink_teardown(struct dsa_switch *ds);
-int sja1105_devlink_param_get(struct dsa_switch *ds, u32 id,
-			      struct devlink_param_gset_ctx *ctx);
-int sja1105_devlink_param_set(struct dsa_switch *ds, u32 id,
-			      struct devlink_param_gset_ctx *ctx);
 int sja1105_devlink_info_get(struct dsa_switch *ds,
 			     struct devlink_info_req *req,
 			     struct netlink_ext_ack *extack);