[net-next 06/15] net/mlx5e: Protect mod header entry flows list with spinlock

[Saeed Mahameed]

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

To remove dependency on rtnl lock, extend mod header entry with spinlock
and use it to protect list of flows attached to mod header 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 | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c 
b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index fe1b04aa910a..09d5cc700297 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -189,6 +189,8 @@ struct mlx5e_mod_hdr_entry {
        /* a node of a hash table which keeps all the mod_hdr entries */
        struct hlist_node mod_hdr_hlist;
 
+       /* protects flows list */
+       spinlock_t flows_lock;
        /* flows sharing the same mod_hdr entry */
        struct list_head flows;
 
@@ -358,6 +360,7 @@ static int mlx5e_attach_mod_hdr(struct mlx5e_priv *priv,
        mh->key.actions = (void *)mh + sizeof(*mh);
        memcpy(mh->key.actions, key.actions, actions_size);
        mh->key.num_actions = num_actions;
+       spin_lock_init(&mh->flows_lock);
        INIT_LIST_HEAD(&mh->flows);
        refcount_set(&mh->refcnt, 1);
 
@@ -372,7 +375,9 @@ static int mlx5e_attach_mod_hdr(struct mlx5e_priv *priv,
 
 attach_flow:
        flow->mh = mh;
+       spin_lock(&mh->flows_lock);
        list_add(&flow->mod_hdr, &mh->flows);
+       spin_unlock(&mh->flows_lock);
        if (is_eswitch_flow)
                flow->esw_attr->mod_hdr_id = mh->mod_hdr_id;
        else
@@ -392,7 +397,9 @@ static void mlx5e_detach_mod_hdr(struct mlx5e_priv *priv,
        if (!flow->mh)
                return;
 
+       spin_lock(&flow->mh->flows_lock);
        list_del(&flow->mod_hdr);
+       spin_unlock(&flow->mh->flows_lock);
 
        mlx5e_mod_hdr_put(priv, flow->mh);
        flow->mh = NULL;
-- 
2.21.0