From 6ba1a4aa5974f8a47e6322cecc965e6357b58d80 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Sat, 16 Jul 2022 21:53:43 +0300 Subject: [PATCH] docs: net: dsa: delete misinformation about -EOPNOTSUPP for FDB/MDB/VLAN Returning -EOPNOTSUPP does *NOT* mean anything special. port_vlan_add() is actually called from 2 code paths, one is vlan_vid_add() from 8021q module and the other is br_switchdev_port_vlan_add() from switchdev. The bridge has a wrapper __vlan_vid_add() which first tries via switchdev, then if that returns -EOPNOTSUPP, tries again via the VLAN RX filters in the 8021q module. But DSA doesn't distinguish between one call path and the other when calling the driver's port_vlan_add(), so if the driver returns -EOPNOTSUPP to switchdev, it also returns -EOPNOTSUPP to the 8021q module. And the latter is a hard error. port_fdb_add() is called from the deferred dsa_owq only, so obviously its return code isn't propagated anywhere, and cannot be interpreted in any way. The return code from port_mdb_add() is propagated to the bridge, but again, this doesn't do anything special when -EOPNOTSUPP is returned, but rather, br_switchdev_mdb_notify() returns void. Signed-off-by: Vladimir Oltean Reviewed-by: Andrew Lunn Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller --- Documentation/networking/dsa/dsa.rst | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/Documentation/networking/dsa/dsa.rst b/Documentation/networking/dsa/dsa.rst index 330a76c2fab6..69ea35e19755 100644 --- a/Documentation/networking/dsa/dsa.rst +++ b/Documentation/networking/dsa/dsa.rst @@ -951,9 +951,7 @@ Bridge VLAN filtering allowed. - ``port_vlan_add``: bridge layer function invoked when a VLAN is configured - (tagged or untagged) for the given switch port. If the operation is not - supported by the hardware, this function should return ``-EOPNOTSUPP`` to - inform the bridge code to fallback to a software implementation. + (tagged or untagged) for the given switch port.. - ``port_vlan_del``: bridge layer function invoked when a VLAN is removed from the given switch port @@ -961,9 +959,7 @@ Bridge VLAN filtering - ``port_fdb_add``: bridge layer function invoked when the bridge wants to install a Forwarding Database entry, the switch hardware should be programmed with the specified address in the specified VLAN Id in the forwarding database - associated with this VLAN ID. If the operation is not supported, this - function should return ``-EOPNOTSUPP`` to inform the bridge code to fallback to - a software implementation. + associated with this VLAN ID. - ``port_fdb_del``: bridge layer function invoked when the bridge wants to remove a Forwarding Database entry, the switch hardware should be programmed to delete @@ -978,9 +974,7 @@ Bridge VLAN filtering the ``bridge fdb show`` command. - ``port_mdb_add``: bridge layer function invoked when the bridge wants to install - a multicast database entry. If the operation is not supported, this function - should return ``-EOPNOTSUPP`` to inform the bridge code to fallback to a - software implementation. The switch hardware should be programmed with the + a multicast database entry. The switch hardware should be programmed with the specified address in the specified VLAN ID in the forwarding database associated with this VLAN ID. -- 2.11.0