[PATCH net] net/mlx5: Do not restore destination-less TC rules

[Tariq Toukan <tariqt@nvidia.com>]

From: Jeroen Massar <jmassar@nvidia.com>

After IPsec policy/state TX rules are added, any TC flow rule, which
forwards packets to uplink, is modified to forward to IPsec TX tables.
As these tables are destroyed dynamically, whenever there is no
reference to them, the destinations of this kind of rules must be
restored to uplink, unless there is no destination for that rule.

The flow rules FLOW_ACTION_ACCEPT, DROP, TRAP, GOTO and SAMPLE do not
have a destination port, and thus out_count = 0.

At cleanup time of the rules in mlx5_esw_ipsec_modify_flow_dests
we call mlx5_eswitch_restore_ipsec_rule but as the above types
do not have a destination we get an underflow of out_count, as
the port is passed, which is esw_attr->out_count - 1.

This change avoids calling mlx5_eswitch_restore_ipsec_rule when
there are no output destinations and thus avoids the underflow.

Fixes: d1569537a837 ("net/mlx5e: Modify and restore TC rules for IPSec TX rules")
Signed-off-by: Jeroen Massar <jmassar@nvidia.com>
Reviewed-by: Jianbo Liu <jianbol@nvidia.com>
Reviewed-by: Cosmin Ratiu <cratiu@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
---
 drivers/net/ethernet/mellanox/mlx5/core/esw/ipsec_fs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/ipsec_fs.c b/drivers/net/ethernet/mellanox/mlx5/core/esw/ipsec_fs.c
index 3cfe743610d3..ab50d2c734ed 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/esw/ipsec_fs.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/ipsec_fs.c
@@ -142,7 +142,8 @@ static int mlx5_esw_ipsec_modify_flow_dests(struct mlx5_eswitch *esw,
 
 	attr = flow->attr;
 	esw_attr = attr->esw_attr;
-	if (esw_attr->out_count - esw_attr->split_count > 1)
+	if (!esw_attr->out_count ||
+	    esw_attr->out_count - esw_attr->split_count > 1)
 		return 0;
 
 	err = mlx5_eswitch_restore_ipsec_rule(esw, flow->rule[0], esw_attr,

base-commit: f5b2772d14884f4be9e718644f1203d4d0e6f0d6
-- 
2.44.0