[PATCH net-next] net: dsa: fix SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING getting ignored

From: Vladimir Oltean <vladimir.oltean@nxp.com>

The bridge emits VLAN filtering events and quite a few others via
switchdev with orig_dev = br->dev. After the blamed commit, these events
started getting ignored.

The point of the patch was to not offload switchdev objects for ports
that didn't go through dsa_port_bridge_join, because the configuration
is unsupported:
- ports that offload a bonding/team interface go through
  dsa_port_bridge_join when that bonding/team interface is later bridged
  with another switch port or LAG
- ports that don't offload LAG don't get notified of the bridge that is
  on top of that LAG.

Sadly, a check is missing, which is that the orig_dev is equal to the
bridge device. This check is compatible with the original intention,
because ports that don't offload bridging because they use a software
LAG don't have dp->bridge_dev set.

On a semi-related note, we should not offload switchdev objects or
populate dp->bridge_dev if the driver doesn't implement .port_bridge_join
either. However there is no regression associated with that, so it can
be done separately.

Fixes: 5696c8aedfcc ("net: dsa: Don't offload port attributes on standalone ports")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 net/dsa/dsa_priv.h | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/net/dsa/dsa_priv.h b/net/dsa/dsa_priv.h
index 2ce46bb87703..1c4ee741b4b8 100644
--- a/net/dsa/dsa_priv.h
+++ b/net/dsa/dsa_priv.h

@@ -182,7 +182,15 @@ static inline bool dsa_port_offloads_netdev(struct dsa_port *dp,
 	/* Switchdev offloading can be configured on: */
 
 	if (dev == dp->slave)
-		/* DSA ports directly connected to a bridge. */
+		/* DSA ports directly connected to a bridge, and event
+		 * was emitted for the ports themselves.
+		 */
+		return true;
+
+	if (dp->bridge_dev == dev)
+		/* DSA ports connected to a bridge, and event was emitted
+		 * for the bridge.
+		 */
 		return true;
 
 	if (dp->lag_dev == dev)

-- 
2.25.1

On Wed, Feb 03, 2021 at 01:31, Vladimir Oltean [off-list ref] wrote:

From: Vladimir Oltean <vladimir.oltean@nxp.com>

The bridge emits VLAN filtering events and quite a few others via
switchdev with orig_dev = br->dev. After the blamed commit, these events
started getting ignored.

The point of the patch was to not offload switchdev objects for ports
that didn't go through dsa_port_bridge_join, because the configuration
is unsupported:
- ports that offload a bonding/team interface go through
  dsa_port_bridge_join when that bonding/team interface is later bridged
  with another switch port or LAG
- ports that don't offload LAG don't get notified of the bridge that is
  on top of that LAG.

Sadly, a check is missing, which is that the orig_dev is equal to the
bridge device. This check is compatible with the original intention,
because ports that don't offload bridging because they use a software
LAG don't have dp->bridge_dev set.

On a semi-related note, we should not offload switchdev objects or
populate dp->bridge_dev if the driver doesn't implement .port_bridge_join
either. However there is no regression associated with that, so it can
be done separately.

Fixes: 5696c8aedfcc ("net: dsa: Don't offload port attributes on standalone ports")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---

Reviewed-by: Tobias Waldekranz <tobias@waldekranz.com>
Tested-by: Tobias Waldekranz <tobias@waldekranz.com>

Hello:

This patch was applied to netdev/net-next.git (refs/heads/master):

On Wed,  3 Feb 2021 01:31:09 +0200 you wrote:

From: Vladimir Oltean <vladimir.oltean@nxp.com>

The bridge emits VLAN filtering events and quite a few others via
switchdev with orig_dev = br->dev. After the blamed commit, these events
started getting ignored.

The point of the patch was to not offload switchdev objects for ports
that didn't go through dsa_port_bridge_join, because the configuration
is unsupported:
- ports that offload a bonding/team interface go through
  dsa_port_bridge_join when that bonding/team interface is later bridged
  with another switch port or LAG
- ports that don't offload LAG don't get notified of the bridge that is
  on top of that LAG.

[...]

Here is the summary with links:
  - [net-next] net: dsa: fix SWITCHDEV_ATTR_ID_BRIDGE_VLAN_FILTERING getting ignored
    https://git.kernel.org/netdev/net-next/c/99b8202b179f

You are awesome, thank you!
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