[PATCH 3/5] qtnfmac: control qtnfmac wireless interfaces bridging

[Sergey Matyukevich <sergey.matyukevich.os@xxxxxxxxxxxxx>]

Bridging qtnfmac interfaces is possible only if the following two
conditions are fulfilled:
- firmware advertises proper support with QLINK_HW_CAPAB_HW_BRIDGE
- kernel is built with CONFIG_NET_SWITCHDEV support

Otherwise adding qtnfmac wireless interfaces into the same bridge
should not be allowed since packets flooded by kernel may break
internal forwarding rules between interfaces.

This patch disables adding qtnfmac wireless interfaces into the
same bridge if no support is provided either by card or by kernel.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich.os@xxxxxxxxxxxxx>
---
 drivers/net/wireless/quantenna/qtnfmac/core.c | 52 +++++++++++++++++----------
 1 file changed, 34 insertions(+), 18 deletions(-)

diff --git a/drivers/net/wireless/quantenna/qtnfmac/core.c b/drivers/net/wireless/quantenna/qtnfmac/core.c
index 9bd4c8f98308..d723438732df 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/core.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/core.c
@@ -225,9 +225,6 @@ static int qtnf_netdev_port_parent_id(struct net_device *ndev,
 	const struct qtnf_vif *vif = qtnf_netdev_get_priv(ndev);
 	const struct qtnf_bus *bus = vif->mac->bus;
 
-	if (!(bus->hw_info.hw_capab & QLINK_HW_CAPAB_HW_BRIDGE))
-		return -EOPNOTSUPP;
-
 	ppid->id_len = sizeof(bus->hw_id);
 	memcpy(&ppid->id, bus->hw_id, ppid->id_len);
 
@@ -665,12 +662,24 @@ bool qtnf_netdev_is_qtn(const struct net_device *ndev)
 	return ndev->netdev_ops == &qtnf_netdev_ops;
 }
 
+static int qtnf_check_br_ports(struct net_device *dev, void *data)
+{
+	struct net_device *ndev = data;
+
+	if (dev != ndev && netdev_port_same_parent_id(dev, ndev))
+		return -ENOTSUPP;
+
+	return 0;
+}
+
 static int qtnf_core_netdevice_event(struct notifier_block *nb,
 				     unsigned long event, void *ptr)
 {
 	struct net_device *ndev = netdev_notifier_info_to_dev(ptr);
 	const struct netdev_notifier_changeupper_info *info;
+	struct net_device *brdev;
 	struct qtnf_vif *vif;
+	struct qtnf_bus *bus;
 	int br_domain;
 	int ret = 0;
 
@@ -681,25 +690,34 @@ static int qtnf_core_netdevice_event(struct notifier_block *nb,
 		return NOTIFY_OK;
 
 	vif = qtnf_netdev_get_priv(ndev);
+	bus = vif->mac->bus;
 
 	switch (event) {
 	case NETDEV_CHANGEUPPER:
 		info = ptr;
+		brdev = info->upper_dev;
 
-		if (!netif_is_bridge_master(info->upper_dev))
+		if (!netif_is_bridge_master(brdev))
 			break;
 
 		pr_debug("[VIF%u.%u] change bridge: %s %s\n",
-			 vif->mac->macid, vif->vifid,
-			 netdev_name(info->upper_dev),
+			 vif->mac->macid, vif->vifid, netdev_name(brdev),
 			 info->linking ? "add" : "del");
 
-		if (info->linking)
-			br_domain = info->upper_dev->ifindex;
-		else
-			br_domain = ndev->ifindex;
+		if (IS_ENABLED(CONFIG_NET_SWITCHDEV) &&
+		    (bus->hw_info.hw_capab & QLINK_HW_CAPAB_HW_BRIDGE)) {
+			if (info->linking)
+				br_domain = brdev->ifindex;
+			else
+				br_domain = ndev->ifindex;
+
+			ret = qtnf_cmd_netdev_changeupper(vif, br_domain);
+		} else {
+			ret = netdev_walk_all_lower_dev(brdev,
+							qtnf_check_br_ports,
+							ndev);
+		}
 
-		ret = qtnf_cmd_netdev_changeupper(vif, br_domain);
 		break;
 	default:
 		break;
@@ -772,13 +790,11 @@ int qtnf_core_attach(struct qtnf_bus *bus)
 		}
 	}
 
-	if (bus->hw_info.hw_capab & QLINK_HW_CAPAB_HW_BRIDGE) {
-		bus->netdev_nb.notifier_call = qtnf_core_netdevice_event;
-		ret = register_netdevice_notifier(&bus->netdev_nb);
-		if (ret) {
-			pr_err("failed to register netdev notifier: %d\n", ret);
-			goto error;
-		}
+	bus->netdev_nb.notifier_call = qtnf_core_netdevice_event;
+	ret = register_netdevice_notifier(&bus->netdev_nb);
+	if (ret) {
+		pr_err("failed to register netdev notifier: %d\n", ret);
+		goto error;
 	}
 
 	bus->fw_state = QTNF_FW_STATE_RUNNING;
-- 
2.11.0