[PATCH 4.4 089/192] [PATCH 093/135] net/mlx5e: Dont modify CQ before it was created

[Greg Kroah-Hartman]

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

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

[ Upstream commit 2fcb92fbd04eef26dfe7e67839da6262d83d6b65 ]

Calling mlx5e_set_coalesce while the interface is down will result in
modifying CQs that don't exist.

Fixes: f62b8bb8f2d3 ('net/mlx5: Extend mlx5_core to support ConnectX-4
Ethernet functionality')
Signed-off-by: Gal Pressman <galp@xxxxxxxxxxxx>

Signed-off-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c
@@ -422,11 +422,15 @@ static int mlx5e_set_coalesce(struct net
 	if (!MLX5_CAP_GEN(mdev, cq_moderation))
 		return -ENOTSUPP;
 
+	mutex_lock(&priv->state_lock);
 	priv->params.tx_cq_moderation_usec = coal->tx_coalesce_usecs;
 	priv->params.tx_cq_moderation_pkts = coal->tx_max_coalesced_frames;
 	priv->params.rx_cq_moderation_usec = coal->rx_coalesce_usecs;
 	priv->params.rx_cq_moderation_pkts = coal->rx_max_coalesced_frames;
 
+	if (!test_bit(MLX5E_STATE_OPENED, &priv->state))
+		goto out;
+
 	for (i = 0; i < priv->params.num_channels; ++i) {
 		c = priv->channel[i];
 
@@ -442,6 +446,8 @@ static int mlx5e_set_coalesce(struct net
 					       coal->rx_max_coalesced_frames);
 	}
 
+out:
+	mutex_unlock(&priv->state_lock);
 	return 0;
 }