[net-next 02/15] net/mlx5e: Protect hairpin entry flows list with spinlock

[Saeed Mahameed]

From: Vlad Buslov <vla...@mellanox.com>

To remove dependency on rtnl lock, extend hairpin entry with spinlock and
use it to protect list of flows attached to hairpin entry from concurrent
modifications.

Signed-off-by: Vlad Buslov <vla...@mellanox.com>
Reviewed-by: Jianbo Liu <jian...@mellanox.com>
Reviewed-by: Roi Dayan <r...@mellanox.com>
Signed-off-by: Saeed Mahameed <sae...@mellanox.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 64ce762ec1e6..0abfa9b3ec54 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -162,6 +162,8 @@ struct mlx5e_hairpin_entry {
        /* a node of a hash table which keeps all the  hairpin entries */
        struct hlist_node hairpin_hlist;
 
+       /* protects flows list */
+       spinlock_t flows_lock;
        /* flows sharing the same hairpin */
        struct list_head flows;
 
@@ -735,6 +737,7 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
        if (!hpe)
                return -ENOMEM;
 
+       spin_lock_init(&hpe->flows_lock);
        INIT_LIST_HEAD(&hpe->flows);
        hpe->peer_vhca_id = peer_id;
        hpe->prio = match_prio;
@@ -782,7 +785,9 @@ static int mlx5e_hairpin_flow_add(struct mlx5e_priv *priv,
                flow->nic_attr->hairpin_tirn = hpe->hp->tirn;
        }
        flow->hpe = hpe;
+       spin_lock(&hpe->flows_lock);
        list_add(&flow->hairpin, &hpe->flows);
+       spin_unlock(&hpe->flows_lock);
 
        return 0;
 
@@ -798,7 +803,10 @@ static void mlx5e_hairpin_flow_del(struct mlx5e_priv *priv,
        if (!flow->hpe)
                return;
 
+       spin_lock(&flow->hpe->flows_lock);
        list_del(&flow->hairpin);
+       spin_unlock(&flow->hpe->flows_lock);
+
        mlx5e_hairpin_put(priv, flow->hpe);
        flow->hpe = NULL;
 }
-- 
2.21.0