From: Vlad Buslov <vladbu@mellanox.com>
Date: Mon, 17 Sep 2018 14:01:58 +0300
Subject: net/mlx5e: Protect tc flow table with mutex
Patch-mainline: v5.4-rc1
Git-commit: b6fac0b46a1a76024698d240f0f9aac552f897b7
References: jsc#SLE-8464

TC flow table is created when first flow is added, and destroyed when last
flow is removed. This assumes that all accesses to the table are externally
synchronized with rtnl lock. To remove dependency on rtnl lock, add new
mutex mlx5e_tc_table->t_lock and use it to protect the flow table.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Reviewed-by: Jianbo Liu <jianbol@mellanox.com>
Reviewed-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/en/fs.h |    2 ++
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c |    7 +++++++
 2 files changed, 9 insertions(+)

--- a/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/fs.h
@@ -10,6 +10,8 @@ enum {
 };
 
 struct mlx5e_tc_table {
+	/* protects flow table */
+	struct mutex			t_lock;
 	struct mlx5_flow_table		*t;
 
 	struct rhashtable               ht;
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -854,6 +854,7 @@ mlx5e_tc_add_nic_flow(struct mlx5e_priv
 			return err;
 	}
 
+	mutex_lock(&priv->fs.tc.t_lock);
 	if (IS_ERR_OR_NULL(priv->fs.tc.t)) {
 		int tc_grp_size, tc_tbl_size;
 		u32 max_flow_counter;
@@ -873,6 +874,7 @@ mlx5e_tc_add_nic_flow(struct mlx5e_priv
 							    MLX5E_TC_TABLE_NUM_GROUPS,
 							    MLX5E_TC_FT_LEVEL, 0);
 		if (IS_ERR(priv->fs.tc.t)) {
+			mutex_unlock(&priv->fs.tc.t_lock);
 			NL_SET_ERR_MSG_MOD(extack,
 					   "Failed to create tc offload table\n");
 			netdev_err(priv->netdev,
@@ -886,6 +888,7 @@ mlx5e_tc_add_nic_flow(struct mlx5e_priv
 
 	flow->rule[0] = mlx5_add_flow_rules(priv->fs.tc.t, &parse_attr->spec,
 					    &flow_act, dest, dest_ix);
+	mutex_unlock(&priv->fs.tc.t_lock);
 
 	if (IS_ERR(flow->rule[0]))
 		return PTR_ERR(flow->rule[0]);
@@ -904,10 +907,12 @@ static void mlx5e_tc_del_nic_flow(struct
 		mlx5_del_flow_rules(flow->rule[0]);
 	mlx5_fc_destroy(priv->mdev, counter);
 
+	mutex_lock(&priv->fs.tc.t_lock);
 	if (!mlx5e_tc_num_filters(priv, MLX5_TC_FLAG(NIC_OFFLOAD)) && priv->fs.tc.t) {
 		mlx5_destroy_flow_table(priv->fs.tc.t);
 		priv->fs.tc.t = NULL;
 	}
+	mutex_unlock(&priv->fs.tc.t_lock);
 
 	if (attr->action & MLX5_FLOW_CONTEXT_ACTION_MOD_HDR)
 		mlx5e_detach_mod_hdr(priv, flow);
@@ -3693,6 +3698,7 @@ int mlx5e_tc_nic_init(struct mlx5e_priv
 	struct mlx5e_tc_table *tc = &priv->fs.tc;
 	int err;
 
+	mutex_init(&tc->t_lock);
 	hash_init(tc->mod_hdr_tbl);
 	hash_init(tc->hairpin_tbl);
 
@@ -3731,6 +3737,7 @@ void mlx5e_tc_nic_cleanup(struct mlx5e_p
 		mlx5_destroy_flow_table(tc->t);
 		tc->t = NULL;
 	}
+	mutex_destroy(&tc->t_lock);
 }
 
 int mlx5e_tc_esw_init(struct rhashtable *tc_ht)