1 files changed, 141 insertions, 119 deletions

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
index 9c54b715228e..decfd82fdef3 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] = {
@@ -51,34 +32,40 @@ 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;
 
-	kfree(port);
-
 	netdev_rx_handler_unregister(real_dev);
 
-	/* release reference on real_dev */
-	dev_put(real_dev);
+	kfree(port);
 
 	netdev_dbg(real_dev, "Removed from rmnet\n");
 	return 0;
 }
 
-static int rmnet_register_real_device(struct net_device *real_dev)
+static int rmnet_register_real_device(struct net_device *real_dev,
+				      struct netlink_ext_ack *extack)
 {
 	struct rmnet_port *port;
 	int rc, entry;
 
 	ASSERT_RTNL();
 
-	if (rmnet_is_real_dev_registered(real_dev))
+	if (rmnet_is_real_dev_registered(real_dev)) {
+		port = rmnet_get_port_rtnl(real_dev);
+		if (port->rmnet_mode != RMNET_EPMODE_VND) {
+			NL_SET_ERR_MSG_MOD(extack, "bridge device already exists");
+			return -EINVAL;
+		}
+
 		return 0;
+	}
 
-	port = kzalloc(sizeof(*port), GFP_ATOMIC);
+	port = kzalloc(sizeof(*port), GFP_KERNEL);
 	if (!port)
 		return -ENOMEM;
 
@@ -89,9 +76,6 @@ static int rmnet_register_real_device(struct net_device *real_dev)
 		return -EBUSY;
 	}
 
-	/* hold on to real dev for MAP data */
-	dev_hold(real_dev);
-
 	for (entry = 0; entry < RMNET_MAX_LOGICAL_EP; entry++)
 		INIT_HLIST_HEAD(&port->muxed_ep[entry]);
 
@@ -99,28 +83,33 @@ 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,
@@ -135,29 +124,38 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 	int err = 0;
 	u16 mux_id;
 
+	if (!tb[IFLA_LINK]) {
+		NL_SET_ERR_MSG_MOD(extack, "link not specified");
+		return -EINVAL;
+	}
+
 	real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
-	if (!real_dev || !dev)
+	if (!real_dev) {
+		NL_SET_ERR_MSG_MOD(extack, "link does not exist");
 		return -ENODEV;
+	}
 
-	if (!data[IFLA_RMNET_MUX_ID])
-		return -EINVAL;
-
-	ep = kzalloc(sizeof(*ep), GFP_ATOMIC);
+	ep = kzalloc(sizeof(*ep), GFP_KERNEL);
 	if (!ep)
 		return -ENOMEM;
 
 	mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
 
-	err = rmnet_register_real_device(real_dev);
+	err = rmnet_register_real_device(real_dev, extack);
 	if (err)
 		goto err0;
 
 	port = rmnet_get_port_rtnl(real_dev);
-	err = rmnet_vnd_newlink(mux_id, dev, port, real_dev, ep);
+	err = rmnet_vnd_newlink(mux_id, dev, port, real_dev, ep, extack);
 	if (err)
 		goto err1;
 
+	err = netdev_upper_dev_link(real_dev, dev, extack);
+	if (err < 0)
+		goto err2;
+
 	port->rmnet_mode = mode;
+	port->rmnet_dev = dev;
 
 	hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
 
@@ -173,8 +171,11 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 
 	return 0;
 
+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;
@@ -183,77 +184,74 @@ 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);
 	}
-	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);
 }
 
-static void rmnet_force_unassociate_device(struct net_device *dev)
+static void rmnet_force_unassociate_device(struct net_device *real_dev)
 {
-	struct net_device *real_dev = dev;
 	struct hlist_node *tmp_ep;
 	struct rmnet_endpoint *ep;
 	struct rmnet_port *port;
 	unsigned long bkt_ep;
 	LIST_HEAD(list);
 
-	if (!rmnet_is_real_dev_registered(real_dev))
-		return;
-
-	ASSERT_RTNL();
-
-	port = rmnet_get_port_rtnl(dev);
-
-	rcu_read_lock();
-	rmnet_unregister_bridge(dev, port);
-
-	hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
-		unregister_netdevice_queue(ep->egress_dev, &list);
-		rmnet_vnd_dellink(ep->mux_id, port, ep);
+	port = rmnet_get_port_rtnl(real_dev);
 
-		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);
 	}
-
-	rcu_read_unlock();
-	unregister_netdevice_many(&list);
-
-	rmnet_unregister_real_device(real_dev, port);
 }
 
 static int rmnet_config_notify_cb(struct notifier_block *nb,
 				  unsigned long event, void *data)
 {
-	struct net_device *dev = netdev_notifier_info_to_dev(data);
+	struct net_device *real_dev = netdev_notifier_info_to_dev(data);
 
-	if (!dev)
+	if (!rmnet_is_real_dev_registered(real_dev))
 		return NOTIFY_DONE;
 
 	switch (event) {
 	case NETDEV_UNREGISTER:
-		netdev_dbg(dev, "Kernel unregister\n");
-		rmnet_force_unassociate_device(dev);
+		netdev_dbg(real_dev, "Kernel unregister\n");
+		rmnet_force_unassociate_device(real_dev);
 		break;
 
 	default:
@@ -272,12 +270,16 @@ static int rmnet_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
 {
 	u16 mux_id;
 
-	if (!data || !data[IFLA_RMNET_MUX_ID])
+	if (!data || !data[IFLA_RMNET_MUX_ID]) {
+		NL_SET_ERR_MSG_MOD(extack, "MUX ID not specified");
 		return -EINVAL;
+	}
 
 	mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
-	if (mux_id > (RMNET_MAX_LOGICAL_EP - 1))
+	if (mux_id > (RMNET_MAX_LOGICAL_EP - 1)) {
+		NL_SET_ERR_MSG_MOD(extack, "invalid MUX ID");
 		return -ERANGE;
+	}
 
 	return 0;
 }
@@ -288,32 +290,41 @@ static int rmnet_changelink(struct net_device *dev, struct nlattr *tb[],
 {
 	struct rmnet_priv *priv = netdev_priv(dev);
 	struct net_device *real_dev;
-	struct rmnet_endpoint *ep;
 	struct rmnet_port *port;
 	u16 mux_id;
 
 	if (!dev)
 		return -ENODEV;
 
-	real_dev = __dev_get_by_index(dev_net(dev),
-				      nla_get_u32(tb[IFLA_LINK]));
-
-	if (!real_dev || !rmnet_is_real_dev_registered(real_dev))
+	real_dev = priv->real_dev;
+	if (!rmnet_is_real_dev_registered(real_dev))
 		return -ENODEV;
 
 	port = rmnet_get_port_rtnl(real_dev);
 
 	if (data[IFLA_RMNET_MUX_ID]) {
 		mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
-		ep = rmnet_get_endpoint(port, priv->mux_id);
-		if (!ep)
-			return -ENODEV;
 
-		hlist_del_init_rcu(&ep->hlnode);
-		hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
+		if (mux_id != priv->mux_id) {
+			struct rmnet_endpoint *ep;
+
+			ep = rmnet_get_endpoint(port, priv->mux_id);
+			if (!ep)
+				return -ENODEV;
 
-		ep->mux_id = mux_id;
-		priv->mux_id = mux_id;
+			if (rmnet_get_endpoint(port, mux_id)) {
+				NL_SET_ERR_MSG_MOD(extack,
+						   "MUX ID already exists");
+				return -EINVAL;
+			}
+
+			hlist_del_init_rcu(&ep->hlnode);
+			hlist_add_head_rcu(&ep->hlnode,
+					   &port->muxed_ep[mux_id]);
+
+			ep->mux_id = mux_id;
+			priv->mux_id = mux_id;
+		}
 	}
 
 	if (data[IFLA_RMNET_FLAGS]) {
@@ -379,11 +390,10 @@ struct rtnl_link_ops rmnet_link_ops __read_mostly = {
 	.fill_info	= rmnet_fill_info,
 };
 
-/* Needs either rcu_read_lock() or rtnl lock */
-struct rmnet_port *rmnet_get_port(struct net_device *real_dev)
+struct rmnet_port *rmnet_get_port_rcu(struct net_device *real_dev)
 {
 	if (rmnet_is_real_dev_registered(real_dev))
-		return rcu_dereference_rtnl(real_dev->rx_handler_data);
+		return rcu_dereference_bh(real_dev->rx_handler_data);
 	else
 		return NULL;
 }
@@ -409,24 +419,43 @@ int rmnet_add_bridge(struct net_device *rmnet_dev,
 	struct rmnet_port *port, *slave_port;
 	int err;
 
-	port = rmnet_get_port(real_dev);
+	port = rmnet_get_port_rtnl(real_dev);
 
 	/* If there is more than one rmnet dev attached, its probably being
 	 * used for muxing. Skip the briding in that case
 	 */
-	if (port->nr_rmnet_devs > 1)
+	if (port->nr_rmnet_devs > 1) {
+		NL_SET_ERR_MSG_MOD(extack, "more than one rmnet dev attached");
 		return -EINVAL;
+	}
+
+	if (port->rmnet_mode != RMNET_EPMODE_VND) {
+		NL_SET_ERR_MSG_MOD(extack, "more than one bridge dev attached");
+		return -EINVAL;
+	}
+
+	if (rmnet_is_real_dev_registered(slave_dev)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "slave cannot be another rmnet dev");
 
-	if (rmnet_is_real_dev_registered(slave_dev))
 		return -EBUSY;
+	}
 
-	err = rmnet_register_real_device(slave_dev);
+	err = rmnet_register_real_device(slave_dev, extack);
 	if (err)
 		return -EBUSY;
 
-	slave_port = rmnet_get_port(slave_dev);
+	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;
@@ -438,16 +467,9 @@ 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(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(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;
@@ -473,8 +495,8 @@ static int __init rmnet_init(void)
 
 static void __exit rmnet_exit(void)
 {
-	unregister_netdevice_notifier(&rmnet_dev_notifier);
 	rtnl_link_unregister(&rmnet_link_ops);
+	unregister_netdevice_notifier(&rmnet_dev_notifier);
 }
 
 module_init(rmnet_init)