Merge branch 'Dynamic-toggling-of-vlan_filtering-for-SJA1105-DSA'

Vladimir Oltean says:

====================
Dynamic toggling of vlan_filtering for SJA1105 DSA

This patchset addresses a limitation in dsa_8021q where this sequence of
commands was causing the switch to stop forwarding traffic:

  ip link add name br0 type bridge vlan_filtering 0
  ip link set dev swp2 master br0
  echo 1 > /sys/class/net/br0/bridge/vlan_filtering
  echo 0 > /sys/class/net/br0/bridge/vlan_filtering

The issue has to do with the VLAN table manipulations that dsa_8021q
does without notifying the bridge layer. The solution is to always
restore the VLANs that the bridge knows about, when disabling tagging.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 84 insertions, 20 deletions

diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index f5b2aeebbfe9..bb98984cd27d 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -1281,6 +1281,8 @@ int br_vlan_get_info(const struct net_device *dev, u16 vid,
 
 	p_vinfo->vid = vid;
 	p_vinfo->flags = v->flags;
+	if (vid == br_get_pvid(vg))
+		p_vinfo->flags |= BRIDGE_VLAN_INFO_PVID;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(br_vlan_get_info);
diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c
index 6ebbd799c4eb..e44e6275b0a1 100644
--- a/net/dsa/tag_8021q.c
+++ b/net/dsa/tag_8021q.c
@@ -91,6 +91,79 @@ int dsa_8021q_rx_source_port(u16 vid)
 }
 EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port);
 
+static int dsa_8021q_restore_pvid(struct dsa_switch *ds, int port)
+{
+	struct bridge_vlan_info vinfo;
+	struct net_device *slave;
+	u16 pvid;
+	int err;
+
+	if (!dsa_is_user_port(ds, port))
+		return 0;
+
+	slave = ds->ports[port].slave;
+
+	err = br_vlan_get_pvid(slave, &pvid);
+	if (err < 0)
+		/* There is no pvid on the bridge for this port, which is
+		 * perfectly valid. Nothing to restore, bye-bye!
+		 */
+		return 0;
+
+	err = br_vlan_get_info(slave, pvid, &vinfo);
+	if (err < 0) {
+		dev_err(ds->dev, "Couldn't determine PVID attributes\n");
+		return err;
+	}
+
+	return dsa_port_vid_add(&ds->ports[port], pvid, vinfo.flags);
+}
+
+/* If @enabled is true, installs @vid with @flags into the switch port's HW
+ * filter.
+ * If @enabled is false, deletes @vid (ignores @flags) from the port. Had the
+ * user explicitly configured this @vid through the bridge core, then the @vid
+ * is installed again, but this time with the flags from the bridge layer.
+ */
+static int dsa_8021q_vid_apply(struct dsa_switch *ds, int port, u16 vid,
+			       u16 flags, bool enabled)
+{
+	struct dsa_port *dp = &ds->ports[port];
+	struct bridge_vlan_info vinfo;
+	int err;
+
+	if (enabled)
+		return dsa_port_vid_add(dp, vid, flags);
+
+	err = dsa_port_vid_del(dp, vid);
+	if (err < 0)
+		return err;
+
+	/* Nothing to restore from the bridge for a non-user port.
+	 * The CPU port VLANs are restored implicitly with the user ports,
+	 * similar to how the bridge does in dsa_slave_vlan_add and
+	 * dsa_slave_vlan_del.
+	 */
+	if (!dsa_is_user_port(ds, port))
+		return 0;
+
+	err = br_vlan_get_info(dp->slave, vid, &vinfo);
+	/* Couldn't determine bridge attributes for this vid,
+	 * it means the bridge had not configured it.
+	 */
+	if (err < 0)
+		return 0;
+
+	/* Restore the VID from the bridge */
+	err = dsa_port_vid_add(dp, vid, vinfo.flags);
+	if (err < 0)
+		return err;
+
+	vinfo.flags &= ~BRIDGE_VLAN_INFO_PVID;
+
+	return dsa_port_vid_add(dp->cpu_dp, vid, vinfo.flags);
+}
+
 /* RX VLAN tagging (left) and TX VLAN tagging (right) setup shown for a single
  * front-panel switch port (here swp0).
  *
@@ -146,8 +219,6 @@ EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port);
 int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
 {
 	int upstream = dsa_upstream_port(ds, port);
-	struct dsa_port *dp = &ds->ports[port];
-	struct dsa_port *upstream_dp = &ds->ports[upstream];
 	u16 rx_vid = dsa_8021q_rx_vid(ds, port);
 	u16 tx_vid = dsa_8021q_tx_vid(ds, port);
 	int i, err;
@@ -164,7 +235,6 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
 	 * restrictions, so there are no concerns about leaking traffic.
 	 */
 	for (i = 0; i < ds->num_ports; i++) {
-		struct dsa_port *other_dp = &ds->ports[i];
 		u16 flags;
 
 		if (i == upstream)
@@ -177,10 +247,7 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
 			/* The RX VID is a regular VLAN on all others */
 			flags = BRIDGE_VLAN_INFO_UNTAGGED;
 
-		if (enabled)
-			err = dsa_port_vid_add(other_dp, rx_vid, flags);
-		else
-			err = dsa_port_vid_del(other_dp, rx_vid);
+		err = dsa_8021q_vid_apply(ds, i, rx_vid, flags, enabled);
 		if (err) {
 			dev_err(ds->dev, "Failed to apply RX VID %d to port %d: %d\n",
 				rx_vid, port, err);
@@ -191,10 +258,7 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
 	/* CPU port needs to see this port's RX VID
 	 * as tagged egress.
 	 */
-	if (enabled)
-		err = dsa_port_vid_add(upstream_dp, rx_vid, 0);
-	else
-		err = dsa_port_vid_del(upstream_dp, rx_vid);
+	err = dsa_8021q_vid_apply(ds, upstream, rx_vid, 0, enabled);
 	if (err) {
 		dev_err(ds->dev, "Failed to apply RX VID %d to port %d: %d\n",
 			rx_vid, port, err);
@@ -202,26 +266,24 @@ int dsa_port_setup_8021q_tagging(struct dsa_switch *ds, int port, bool enabled)
 	}
 
 	/* Finally apply the TX VID on this port and on the CPU port */
-	if (enabled)
-		err = dsa_port_vid_add(dp, tx_vid, BRIDGE_VLAN_INFO_UNTAGGED);
-	else
-		err = dsa_port_vid_del(dp, tx_vid);
+	err = dsa_8021q_vid_apply(ds, port, tx_vid, BRIDGE_VLAN_INFO_UNTAGGED,
+				  enabled);
 	if (err) {
 		dev_err(ds->dev, "Failed to apply TX VID %d on port %d: %d\n",
 			tx_vid, port, err);
 		return err;
 	}
-	if (enabled)
-		err = dsa_port_vid_add(upstream_dp, tx_vid, 0);
-	else
-		err = dsa_port_vid_del(upstream_dp, tx_vid);
+	err = dsa_8021q_vid_apply(ds, upstream, tx_vid, 0, enabled);
 	if (err) {
 		dev_err(ds->dev, "Failed to apply TX VID %d on port %d: %d\n",
 			tx_vid, upstream, err);
 		return err;
 	}
 
-	return 0;
+	if (!enabled)
+		err = dsa_8021q_restore_pvid(ds, port);
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(dsa_port_setup_8021q_tagging);