Patch "net/mlx5e: Fix minimum MTU" has been added to the 4.5-stable tree

This is a note to let you know that I've just added the patch titled

net/mlx5e: Fix minimum MTU

to the 4.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
net-mlx5e-fix-minimum-mtu.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Saeed Mahameed <[email protected]>
Date: Fri, 22 Apr 2016 00:33:04 +0300
Subject: net/mlx5e: Fix minimum MTU

From: Saeed Mahameed <[email protected]>

[ Upstream commit d8edd2469ace550db707798180d1c84d81f93bca ]

Minimum MTU that can be set in Connectx4 device is 68.

This fixes the case where a user wants to set invalid MTU, the driver will fail to satisfy this request and the interface will stay down.

It is better to report an error and continue working with old mtu.

---
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

@@ -1906,22 +1906,27 @@ static int mlx5e_set_features(struct net
 	return err;
 }
 
+#define MXL5_HW_MIN_MTU 64
+#define MXL5E_MIN_MTU (MXL5_HW_MIN_MTU + ETH_FCS_LEN)
+
 static int mlx5e_change_mtu(struct net_device *netdev, int new_mtu)
 {
 	struct mlx5e_priv *priv = netdev_priv(netdev);
 	struct mlx5_core_dev *mdev = priv->mdev;
 	bool was_opened;
 	u16 max_mtu;
+	u16 min_mtu;
 	int err = 0;
 
 	mlx5_query_port_max_mtu(mdev, &max_mtu, 1);
 
 	max_mtu = MLX5E_HW2SW_MTU(max_mtu);
+	min_mtu = MLX5E_HW2SW_MTU(MXL5E_MIN_MTU);
 
-	if (new_mtu > max_mtu) {
+	if (new_mtu > max_mtu || new_mtu < min_mtu) {
 		netdev_err(netdev,
-			   "%s: Bad MTU (%d) > (%d) Max\n",
-			   __func__, new_mtu, max_mtu);
+			   "%s: Bad MTU (%d), valid range is: [%d..%d]\n",
+			   __func__, new_mtu, min_mtu, max_mtu);
 		return -EINVAL;
 	}
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.5/net-mlx5e-device-s-mtu-field-is-u16-and-not-int.patch queue-4.5/net-mlx5e-use-vport-mtu-rather-than-physical-port-mtu.patch queue-4.5/net-mlx5e-fix-minimum-mtu.patch queue-4.5/net-mlx5_core-fix-soft-lockup-in-steering-error-flow.patch