From: Vlad Buslov <vladbu@mellanox.com>
Date: Tue, 12 Mar 2019 11:40:12 +0200
Subject: net/mlx5e: Rely on rcu instead of rtnl lock when getting upper dev
Patch-mainline: v5.4-rc1
Git-commit: fa833bd52b7b58d8311bf6a0be29a32e62a1f289
References: jsc#SLE-8464

Function netdev_master_upper_dev_get() generates warning if caller doesn't
hold rtnl lock. Modify rules update path to use rcu version of that
function.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c |   14 +++++++++++++-
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c     |    6 +++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_tun.c
@@ -31,11 +31,23 @@ static int get_route_and_out_devs(struct
 
 	real_dev = is_vlan_dev(dev) ? vlan_dev_real_dev(dev) : dev;
 	uplink_dev = mlx5_eswitch_uplink_get_proto_dev(esw, REP_ETH);
-	uplink_upper = netdev_master_upper_dev_get(uplink_dev);
+
+	rcu_read_lock();
+	uplink_upper = netdev_master_upper_dev_get_rcu(uplink_dev);
+	/* mlx5_lag_is_sriov() is a blocking function which can't be called
+	 * while holding rcu read lock. Take the net_device for correctness
+	 * sake.
+	 */
+	if (uplink_upper)
+		dev_hold(uplink_upper);
+	rcu_read_unlock();
+
 	dst_is_lag_dev = (uplink_upper &&
 			  netif_is_lag_master(uplink_upper) &&
 			  real_dev == uplink_upper &&
 			  mlx5_lag_is_sriov(priv->mdev));
+	if (uplink_upper)
+		dev_put(uplink_upper);
 
 	/* if the egress device isn't on the same HW e-switch or
 	 * it's a LAG device, use the uplink
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -2987,12 +2987,16 @@ static int parse_tc_fdb_actions(struct m
 			if (netdev_port_same_parent_id(priv->netdev, out_dev)) {
 				struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
 				struct net_device *uplink_dev = mlx5_eswitch_uplink_get_proto_dev(esw, REP_ETH);
-				struct net_device *uplink_upper = netdev_master_upper_dev_get(uplink_dev);
+				struct net_device *uplink_upper;
 
+				rcu_read_lock();
+				uplink_upper =
+					netdev_master_upper_dev_get_rcu(uplink_dev);
 				if (uplink_upper &&
 				    netif_is_lag_master(uplink_upper) &&
 				    uplink_upper == out_dev)
 					out_dev = uplink_dev;
+				rcu_read_unlock();
 
 				if (is_vlan_dev(out_dev)) {
 					err = add_vlan_push_action(priv, attr,