[net-next 06/14] net/mlx5e: Avoid false lock depenency warning on tc_ht
From: Saeed Mahameed <saeed@kernel.org>
Date: 2021-02-02 06:57:18
Subsystem:
mellanox ethernet driver (mlx5e), mellanox mlx5 core vpi driver, networking drivers, the rest · Maintainers:
Saeed Mahameed, Tariq Toukan, Mark Bloch, Leon Romanovsky, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Roi Dayan <redacted>
To avoid false lock dependency warning set the tc_ht lock
class different than the lock class of the ht being used when deleting
last flow from a group and then deleting a group, we get into del_sw_flow_group()
which call rhashtable_destroy on fg->ftes_hash which will take ht->mutex but
it's different than the ht->mutex here.
======================================================
WARNING: possible circular locking dependency detected
5.11.0-rc4_net_next_mlx5_949fdcc #1 Not tainted
------------------------------------------------------
modprobe/12950 is trying to acquire lock:
ffff88816510f910 (&node->lock){++++}-{3:3}, at: mlx5_del_flow_rules+0x2a/0x210 [mlx5_core]
but task is already holding lock:
ffff88815834e3e8 (&ht->mutex){+.+.}-{3:3}, at: rhashtable_free_and_destroy+0x37/0x340
which lock already depends on the new lock.
Signed-off-by: Roi Dayan <redacted>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 8fd38ad8113b..280ea1e1e039 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c@@ -190,6 +190,14 @@ struct mlx5e_tc_attr_to_reg_mapping mlx5e_tc_attr_to_reg_mappings[] = { [NIC_ZONE_RESTORE_TO_REG] = nic_zone_restore_to_reg_ct, }; +/* To avoid false lock dependency warning set the tc_ht lock + * class different than the lock class of the ht being used when deleting + * last flow from a group and then deleting a group, we get into del_sw_flow_group() + * which call rhashtable_destroy on fg->ftes_hash which will take ht->mutex but + * it's different than the ht->mutex here. + */ +static struct lock_class_key tc_ht_lock_key; + static void mlx5e_put_flow_tunnel_id(struct mlx5e_tc_flow *flow); void
@@ -5215,6 +5223,8 @@ int mlx5e_tc_nic_init(struct mlx5e_priv *priv) if (err) return err; + lockdep_set_class(&tc->ht.mutex, &tc_ht_lock_key); + if (MLX5_CAP_FLOWTABLE_NIC_RX(priv->mdev, ignore_flow_level)) { attr.flags = MLX5_CHAINS_AND_PRIOS_SUPPORTED | MLX5_CHAINS_IGNORE_FLOW_LEVEL_SUPPORTED;
@@ -5333,6 +5343,8 @@ int mlx5e_tc_esw_init(struct rhashtable *tc_ht) if (err) goto err_ht_init; + lockdep_set_class(&tc_ht->mutex, &tc_ht_lock_key); + return err; err_ht_init:
--
2.29.2