From: Adi Nissim <adin@mellanox.com>
Date: Tue, 5 Jun 2018 11:32:11 +0300
Subject: net/mlx5e: Fix null pointer access when setting MTU of vport
 representor
Patch-mainline: v4.18-rc8
Git-commit: eacecf2760e321bf1c99b981d44a14bd05721f15
References: bsc#1103990 FATE#326006

MTU helper function is used by both conventional mlx5e
instances (PF/VF) and the eswitch representors. The representor
shouldn't change the nic vport context MTU, the VF is responsible for
that. Therefore set_mtu_cb has a null value when changing the
representor MTU.

Fixes: 250a42b6a764 ("net/mlx5e: Support configurable MTU for vport representors")
Signed-off-by: Adi Nissim <adin@mellanox.com>
Reviewed-by: Yevgeny Kliteynik <kliteyn@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -3712,7 +3712,8 @@ int mlx5e_change_mtu(struct net_device *
 
 	if (!reset) {
 		params->sw_mtu = new_mtu;
-		set_mtu_cb(priv);
+		if (set_mtu_cb)
+			set_mtu_cb(priv);
 		netdev->mtu = params->sw_mtu;
 		goto out;
 	}