Merge branch 'qualcomm-rmnet-Fix-issues-with-CONFIG_DEBUG_PREEMPT-enabled'

Subash Abhinov Kasiviswanathan says:

====================
net: qualcomm: rmnet: Fix issues with CONFIG_DEBUG_PREEMPT enabled

Patch 1 and 2 fixes issues identified when CONFIG_DEBUG_PREEMPT was
enabled. These involve APIs which were called in invalid contexts.

Patch 3 is a null derefence fix identified by code inspection.
====================

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

3 files changed, 20 insertions, 55 deletions

diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
index 7e7704daf5f1..c4949183eef3 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c
@@ -43,12 +43,6 @@
 
 /* Local Definitions and Declarations */
 
-struct rmnet_walk_data {
-	struct net_device *real_dev;
-	struct list_head *head;
-	struct rmnet_port *port;
-};
-
 static int rmnet_is_real_dev_registered(const struct net_device *real_dev)
 {
 	return rcu_access_pointer(real_dev->rx_handler) == rmnet_rx_handler;
@@ -112,17 +106,14 @@ static int rmnet_register_real_device(struct net_device *real_dev)
 static void rmnet_unregister_bridge(struct net_device *dev,
 				    struct rmnet_port *port)
 {
-	struct net_device *rmnet_dev, *bridge_dev;
 	struct rmnet_port *bridge_port;
+	struct net_device *bridge_dev;
 
 	if (port->rmnet_mode != RMNET_EPMODE_BRIDGE)
 		return;
 
 	/* bridge slave handling */
 	if (!port->nr_rmnet_devs) {
-		rmnet_dev = netdev_master_upper_dev_get_rcu(dev);
-		netdev_upper_dev_unlink(dev, rmnet_dev);
-
 		bridge_dev = port->bridge_ep;
 
 		bridge_port = rmnet_get_port_rtnl(bridge_dev);
@@ -132,9 +123,6 @@ static void rmnet_unregister_bridge(struct net_device *dev,
 		bridge_dev = port->bridge_ep;
 
 		bridge_port = rmnet_get_port_rtnl(bridge_dev);
-		rmnet_dev = netdev_master_upper_dev_get_rcu(bridge_dev);
-		netdev_upper_dev_unlink(bridge_dev, rmnet_dev);
-
 		rmnet_unregister_real_device(bridge_dev, bridge_port);
 	}
 }
@@ -173,10 +161,6 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 	if (err)
 		goto err1;
 
-	err = netdev_master_upper_dev_link(dev, real_dev, NULL, NULL, extack);
-	if (err)
-		goto err2;
-
 	port->rmnet_mode = mode;
 
 	hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
@@ -193,8 +177,6 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev,
 
 	return 0;
 
-err2:
-	rmnet_vnd_dellink(mux_id, port, ep);
 err1:
 	rmnet_unregister_real_device(real_dev, port);
 err0:
@@ -204,14 +186,13 @@ 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 rmnet_endpoint *ep;
 	struct rmnet_port *port;
 	u8 mux_id;
 
-	rcu_read_lock();
-	real_dev = netdev_master_upper_dev_get_rcu(dev);
-	rcu_read_unlock();
+	real_dev = priv->real_dev;
 
 	if (!real_dev || !rmnet_is_real_dev_registered(real_dev))
 		return;
@@ -219,7 +200,6 @@ static void rmnet_dellink(struct net_device *dev, struct list_head *head)
 	port = rmnet_get_port_rtnl(real_dev);
 
 	mux_id = rmnet_vnd_get_mux(dev);
-	netdev_upper_dev_unlink(dev, real_dev);
 
 	ep = rmnet_get_endpoint(port, mux_id);
 	if (ep) {
@@ -233,30 +213,13 @@ static void rmnet_dellink(struct net_device *dev, struct list_head *head)
 	unregister_netdevice_queue(dev, head);
 }
 
-static int rmnet_dev_walk_unreg(struct net_device *rmnet_dev, void *data)
-{
-	struct rmnet_walk_data *d = data;
-	struct rmnet_endpoint *ep;
-	u8 mux_id;
-
-	mux_id = rmnet_vnd_get_mux(rmnet_dev);
-	ep = rmnet_get_endpoint(d->port, mux_id);
-	if (ep) {
-		hlist_del_init_rcu(&ep->hlnode);
-		rmnet_vnd_dellink(mux_id, d->port, ep);
-		kfree(ep);
-	}
-	netdev_upper_dev_unlink(rmnet_dev, d->real_dev);
-	unregister_netdevice_queue(rmnet_dev, d->head);
-
-	return 0;
-}
-
 static void rmnet_force_unassociate_device(struct net_device *dev)
 {
 	struct net_device *real_dev = dev;
-	struct rmnet_walk_data d;
+	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))
@@ -264,16 +227,19 @@ static void rmnet_force_unassociate_device(struct net_device *dev)
 
 	ASSERT_RTNL();
 
-	d.real_dev = real_dev;
-	d.head = &list;
-
 	port = rmnet_get_port_rtnl(dev);
-	d.port = port;
 
 	rcu_read_lock();
 	rmnet_unregister_bridge(dev, port);
 
-	netdev_walk_all_lower_dev_rcu(real_dev, rmnet_dev_walk_unreg, &d);
+	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);
+
+		hlist_del_init_rcu(&ep->hlnode);
+		kfree(ep);
+	}
+
 	rcu_read_unlock();
 	unregister_netdevice_many(&list);
 
@@ -422,11 +388,6 @@ 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)
-		return -EINVAL;
-
 	slave_port = rmnet_get_port(slave_dev);
 	slave_port->rmnet_mode = RMNET_EPMODE_BRIDGE;
 	slave_port->bridge_ep = real_dev;
@@ -449,7 +410,6 @@ int rmnet_del_bridge(struct net_device *rmnet_dev,
 	port->rmnet_mode = RMNET_EPMODE_VND;
 	port->bridge_ep = NULL;
 
-	netdev_upper_dev_unlink(slave_dev, rmnet_dev);
 	slave_port = rmnet_get_port(slave_dev);
 	rmnet_unregister_real_device(slave_dev, slave_port);
 
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
index 6bc328fb88e1..b0dbca070c00 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c
@@ -38,6 +38,11 @@ static u8 rmnet_map_do_flow_control(struct sk_buff *skb,
 	}
 
 	ep = rmnet_get_endpoint(port, mux_id);
+	if (!ep) {
+		kfree_skb(skb);
+		return RX_HANDLER_CONSUMED;
+	}
+
 	vnd = ep->egress_dev;
 
 	ip_family = cmd->flow_control.ip_family;
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
index 570a227acdd8..346d310914df 100644
--- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
+++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_vnd.c
@@ -121,7 +121,7 @@ static void rmnet_get_stats64(struct net_device *dev,
 	memset(&total_stats, 0, sizeof(struct rmnet_vnd_stats));
 
 	for_each_possible_cpu(cpu) {
-		pcpu_ptr = this_cpu_ptr(priv->pcpu_stats);
+		pcpu_ptr = per_cpu_ptr(priv->pcpu_stats, cpu);
 
 		do {
 			start = u64_stats_fetch_begin_irq(&pcpu_ptr->syncp);