1 files changed, 63 insertions, 68 deletions

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
index e3fbf2331b96..fbf4cbcf1a65 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
@@ -13,25 +13,6 @@
 #include "rmnet_vnd.h"
 #include "rmnet_private.h"
 
-/* Locking scheme -
- * The shared resource which needs to be protected is realdev->rx_handler_data.
- * For the writer path, this is using rtnl_lock(). The writer paths are
- * rmnet_newlink(), rmnet_dellink() and rmnet_force_unassociate_device(). These
- * paths are already called with rtnl_lock() acquired in. There is also an
- * ASSERT_RTNL() to ensure that we are calling with rtnl acquired. For
- * dereference here, we will need to use rtnl_dereference(). Dev list writing
- * needs to happen with rtnl_lock() acquired for netdev_master_upper_dev_link().
- * For the reader path, the real_dev->rx_handler_data is called in the TX / RX
- * path. We only need rcu_read_lock() for these scenarios. In these cases,
- * the rcu_read_lock() is held in __dev_queue_xmit() and
- * netif_receive_skb_internal(), so readers need to use rcu_dereference_rtnl()
- * to get the relevant information. For dev list reading, we again acquire
- * rcu_read_lock() in rmnet_dellink() for netdev_master_upper_dev_get_rcu().
- * We also use unregister_netdevice_many() to free all rmnet devices in
- * rmnet_force_unassociate_device() so we dont lose the rtnl_lock() and free in
- * same context.
- */
-
 /* Local Definitions and Declarations */
 
 static const struct nla_policy rmnet_policy[IFLA_RMNET_MAX + 1] = {
@@ -51,9 +32,10 @@ rmnet_get_port_rtnl(const struct net_device *real_dev)
 	return rtnl_dereference(real_dev->rx_handler_data);
 }
 
-static int rmnet_unregister_real_device(struct net_device *real_dev,
-					struct rmnet_port *port)
+static int rmnet_unregister_real_device(struct net_device *real_dev)
 {
+	struct rmnet_port *port = rmnet_get_port_rtnl(real_dev);
+
 	if (port->nr_rmnet_devs)
 		return -EINVAL;
 
@@ -93,28 +75,33 @@ static int rmnet_register_real_device(struct net_device *real_dev)
 	return 0;
 }
 
-static void rmnet_unregister_bridge(struct net_device *dev,
-				    struct rmnet_port *port)
+static void rmnet_unregister_bridge(struct rmnet_port *port)
 {
-	struct rmnet_port *bridge_port;
-	struct net_device *bridge_dev;
+	struct net_device *bridge_dev, *real_dev, *rmnet_dev;
+	struct rmnet_port *real_port;
 
 	if (port->rmnet_mode != RMNET_EPMODE_BRIDGE)
 		return;
 
-	/* bridge slave handling */
+	rmnet_dev = port->rmnet_dev;
 	if (!port->nr_rmnet_devs) {
-		bridge_dev = port->bridge_ep;
+		/* bridge device */
+		real_dev = port->bridge_ep;
+		bridge_dev = port->dev;
 
-		bridge_port = rmnet_get_port_rtnl(bridge_dev);
-		bridge_port->bridge_ep = NULL;
-		bridge_port->rmnet_mode = RMNET_EPMODE_VND;
+		real_port = rmnet_get_port_rtnl(real_dev);
+		real_port->bridge_ep = NULL;
+		real_port->rmnet_mode = RMNET_EPMODE_VND;
 	} else {
+		/* real device */
 		bridge_dev = port->bridge_ep;
 
-		bridge_port = rmnet_get_port_rtnl(bridge_dev);
-		rmnet_unregister_real_device(bridge_dev, bridge_port);
+		port->bridge_ep = NULL;
+		port->rmnet_mode = RMNET_EPMODE_VND;
 	}
+
+	netdev_upper_dev_unlink(bridge_dev, rmnet_dev);
+	rmnet_unregister_real_device(bridge_dev);
 }
 
 static int rmnet_newlink(struct net *src_net, struct net_device *dev,
@@ -161,6 +148,7 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 		goto err2;
 
 	port->rmnet_mode = mode;
+	port->rmnet_dev = dev;
 
 	hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
 
@@ -178,8 +166,9 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 
 err2:
 	unregister_netdevice(dev);
+	rmnet_vnd_dellink(mux_id, port, ep);
 err1:
-	rmnet_unregister_real_device(real_dev, port);
+	rmnet_unregister_real_device(real_dev);
 err0:
 	kfree(ep);
 	return err;
@@ -188,30 +177,32 @@ err0:
 static void rmnet_dellink(struct net_device *dev, struct list_head *head)
 {
 	struct rmnet_priv *priv = netdev_priv(dev);
-	struct net_device *real_dev;
+	struct net_device *real_dev, *bridge_dev;
+	struct rmnet_port *real_port, *bridge_port;
 	struct rmnet_endpoint *ep;
-	struct rmnet_port *port;
-	u8 mux_id;
+	u8 mux_id = priv->mux_id;
 
 	real_dev = priv->real_dev;
 
-	if (!real_dev || !rmnet_is_real_dev_registered(real_dev))
+	if (!rmnet_is_real_dev_registered(real_dev))
 		return;
 
-	port = rmnet_get_port_rtnl(real_dev);
-
-	mux_id = rmnet_vnd_get_mux(dev);
+	real_port = rmnet_get_port_rtnl(real_dev);
+	bridge_dev = real_port->bridge_ep;
+	if (bridge_dev) {
+		bridge_port = rmnet_get_port_rtnl(bridge_dev);
+		rmnet_unregister_bridge(bridge_port);
+	}
 
-	ep = rmnet_get_endpoint(port, mux_id);
+	ep = rmnet_get_endpoint(real_port, mux_id);
 	if (ep) {
 		hlist_del_init_rcu(&ep->hlnode);
-		rmnet_unregister_bridge(dev, port);
-		rmnet_vnd_dellink(mux_id, port, ep);
+		rmnet_vnd_dellink(mux_id, real_port, ep);
 		kfree(ep);
 	}
-	netdev_upper_dev_unlink(real_dev, dev);
-	rmnet_unregister_real_device(real_dev, port);
 
+	netdev_upper_dev_unlink(real_dev, dev);
+	rmnet_unregister_real_device(real_dev);
 	unregister_netdevice_queue(dev, head);
 }
 
@@ -223,23 +214,23 @@ static void rmnet_force_unassociate_device(struct net_device *real_dev)
 	unsigned long bkt_ep;
 	LIST_HEAD(list);
 
-	ASSERT_RTNL();
-
 	port = rmnet_get_port_rtnl(real_dev);
 
-	rmnet_unregister_bridge(real_dev, port);
-
-	hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
-		netdev_upper_dev_unlink(real_dev, ep->egress_dev);
-		unregister_netdevice_queue(ep->egress_dev, &list);
-		rmnet_vnd_dellink(ep->mux_id, port, ep);
-		hlist_del_init_rcu(&ep->hlnode);
-		kfree(ep);
+	if (port->nr_rmnet_devs) {
+		/* real device */
+		rmnet_unregister_bridge(port);
+		hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
+			unregister_netdevice_queue(ep->egress_dev, &list);
+			netdev_upper_dev_unlink(real_dev, ep->egress_dev);
+			rmnet_vnd_dellink(ep->mux_id, port, ep);
+			hlist_del_init_rcu(&ep->hlnode);
+			kfree(ep);
+		}
+		rmnet_unregister_real_device(real_dev);
+		unregister_netdevice_many(&list);
+	} else {
+		rmnet_unregister_bridge(port);
 	}
-
-	unregister_netdevice_many(&list);
-
-	rmnet_unregister_real_device(real_dev, port);
 }
 
 static int rmnet_config_notify_cb(struct notifier_block *nb,
@@ -418,6 +409,9 @@ int rmnet_add_bridge(struct net_device *rmnet_dev,
 	if (port->nr_rmnet_devs > 1)
 		return -EINVAL;
 
+	if (port->rmnet_mode != RMNET_EPMODE_VND)
+		return -EINVAL;
+
 	if (rmnet_is_real_dev_registered(slave_dev))
 		return -EBUSY;
 
@@ -425,9 +419,17 @@ int rmnet_add_bridge(struct net_device *rmnet_dev,
 	if (err)
 		return -EBUSY;
 
+	err = netdev_master_upper_dev_link(slave_dev, rmnet_dev, NULL, NULL,
+					   extack);
+	if (err) {
+		rmnet_unregister_real_device(slave_dev);
+		return err;
+	}
+
 	slave_port = rmnet_get_port_rtnl(slave_dev);
 	slave_port->rmnet_mode = RMNET_EPMODE_BRIDGE;
 	slave_port->bridge_ep = real_dev;
+	slave_port->rmnet_dev = rmnet_dev;
 
 	port->rmnet_mode = RMNET_EPMODE_BRIDGE;
 	port->bridge_ep = slave_dev;
@@ -439,16 +441,9 @@ int rmnet_add_bridge(struct net_device *rmnet_dev,
 int rmnet_del_bridge(struct net_device *rmnet_dev,
 		     struct net_device *slave_dev)
 {
-	struct rmnet_priv *priv = netdev_priv(rmnet_dev);
-	struct net_device *real_dev = priv->real_dev;
-	struct rmnet_port *port, *slave_port;
-
-	port = rmnet_get_port_rtnl(real_dev);
-	port->rmnet_mode = RMNET_EPMODE_VND;
-	port->bridge_ep = NULL;
+	struct rmnet_port *port = rmnet_get_port_rtnl(slave_dev);
 
-	slave_port = rmnet_get_port_rtnl(slave_dev);
-	rmnet_unregister_real_device(slave_dev, slave_port);
+	rmnet_unregister_bridge(port);
 
 	netdev_dbg(slave_dev, "removed from rmnet as slave\n");
 	return 0;