From: Moshe Shemesh <moshe@mellanox.com>
Date: Thu, 15 Feb 2018 12:41:48 +0200
Subject: net/mlx5e: Verify coalescing parameters in range
Patch-mainline: v4.16
Git-commit: b392a2078b5e0094ff38aa0c9d2a31b3f607d4ef
References: bsc#1103990 FATE#326006

Add check of coalescing parameters received through ethtool are within
range of values supported by the HW.
Driver gets the coalescing rx/tx-usecs and rx/tx-frames as set by the
users through ethtool. The ethtool support up to 32 bit value for each.
However, mlx5 modify cq limits the coalescing time parameter to 12 bit
and coalescing frames parameters to 16 bits.
Return out of range error if user tries to set these parameters to
higher values.

Fixes: f62b8bb8f2d3 ('net/mlx5: Extend mlx5_core to support ConnectX-4 Ethernet functionality')
Signed-off-by: Moshe Shemesh <moshe@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -477,6 +477,9 @@ static int mlx5e_get_coalesce(struct net
 	return mlx5e_ethtool_get_coalesce(priv, coal);
 }
 
+#define MLX5E_MAX_COAL_TIME		MLX5_MAX_CQ_PERIOD
+#define MLX5E_MAX_COAL_FRAMES		MLX5_MAX_CQ_COUNT
+
 static void
 mlx5e_set_priv_channels_coalesce(struct mlx5e_priv *priv, struct ethtool_coalesce *coal)
 {
@@ -511,6 +514,20 @@ int mlx5e_ethtool_set_coalesce(struct ml
 	if (!MLX5_CAP_GEN(mdev, cq_moderation))
 		return -EOPNOTSUPP;
 
+	if (coal->tx_coalesce_usecs > MLX5E_MAX_COAL_TIME ||
+	    coal->rx_coalesce_usecs > MLX5E_MAX_COAL_TIME) {
+		netdev_info(priv->netdev, "%s: maximum coalesce time supported is %lu usecs\n",
+			    __func__, MLX5E_MAX_COAL_TIME);
+		return -ERANGE;
+	}
+
+	if (coal->tx_max_coalesced_frames > MLX5E_MAX_COAL_FRAMES ||
+	    coal->rx_max_coalesced_frames > MLX5E_MAX_COAL_FRAMES) {
+		netdev_info(priv->netdev, "%s: maximum coalesced frames supported is %lu\n",
+			    __func__, MLX5E_MAX_COAL_FRAMES);
+		return -ERANGE;
+	}
+
 	mutex_lock(&priv->state_lock);
 	new_channels.params = priv->channels.params;