[PATCH][Vivid] net/mlx4_en: Disbale GRO for incoming loopback/selftest packets

[Rafael David Tinoco]

BugLink: https://bugs.launchpad.net/bugs/1432848

Packets which are sent from the selftest (ethtool) flow,
should not be passed to GRO stack but rather dropped by
the driver after validation. To achieve that, we disable
GRO for the duration of the selftest.

Fixes: dd65beac48a5 ("net/mlx4_en: Extend usage of napi_gro_frags")
Reported-by: Carol Soto <clsoto at linux.vnet.ibm.com>
OriginalAuthor: Ido Shamay <idos at mellanox.com>
(backported from commit 1037ebbbd262227a91dfdd558159e345d4edf6b7 upstream)
Signed-off-by: Ido Shamay <idos at mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz at mellanox.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Rafael David Tinoco <rafael.tinoco at canonical.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_selftest.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_selftest.c b/drivers/net/ethernet/mellanox/mlx4/en_selftest.c
index 2d8ee66..a61009f 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_selftest.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_selftest.c
@@ -81,12 +81,14 @@ static int mlx4_en_test_loopback(struct mlx4_en_priv *priv)
 {
 	u32 loopback_ok = 0;
 	int i;
-
+	bool gro_enabled;
 
         priv->loopback_ok = 0;
 	priv->validate_loopback = 1;
+	gro_enabled = priv->dev->features & NETIF_F_GRO;
 
 	mlx4_en_update_loopback_state(priv->dev, priv->dev->features);
+	priv->dev->features &= ~NETIF_F_GRO;
 
 	/* xmit */
 	if (mlx4_en_test_loopback_xmit(priv)) {
@@ -108,6 +110,10 @@ static int mlx4_en_test_loopback(struct mlx4_en_priv *priv)
 mlx4_en_test_loopback_exit:
 
 	priv->validate_loopback = 0;
+
+	if (gro_enabled)
+		priv->dev->features |= NETIF_F_GRO;
+
 	mlx4_en_update_loopback_state(priv->dev, priv->dev->features);
 	return !loopback_ok;
 }
-- 
2.1.4