[PATCH 4.17 020/101] net/mlx5e: Dont attempt to dereference the ppriv struct if not being eswitch manager

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>

[ Upstream commit 8ffd569aaa818f2624ca821d9a246342fa8b8c50 ]

The check for cpu hit statistics was not returning immediate false for
any non vport rep netdev and hence we crashed (say on mlx5 probed VFs) if
user-space tool was calling into any possible netdev in the system.

Fix that by doing a proper check before dereferencing.

Fixes: 1d447a39142e ('net/mlx5e: Extendable vport representor netdev private data')
Signed-off-by: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Reported-by: Eli Cohen <eli@xxxxxxxxxxxxx>
Reviewed-by: Eli Cohen <eli@xxxxxxxxxxxxx>
Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rep.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
@@ -804,8 +804,12 @@ bool mlx5e_is_uplink_rep(struct mlx5e_pr
 static bool mlx5e_is_vf_vport_rep(struct mlx5e_priv *priv)
 {
 	struct mlx5e_rep_priv *rpriv = priv->ppriv;
-	struct mlx5_eswitch_rep *rep = rpriv->rep;
+	struct mlx5_eswitch_rep *rep;
 
+	if (!MLX5_CAP_GEN(priv->mdev, eswitch_flow_table))
+		return false;
+
+	rep = rpriv->rep;
 	if (rep && rep->vport != FDB_UPLINK_VPORT)
 		return true;