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net/mlx5e: Avoid false lock depenency warning on tc_ht

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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 <roid@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
This commit is contained in:
Roi Dayan 2021-01-25 11:28:07 +02:00 committed by Saeed Mahameed
parent 84db661247
commit 9ba33339c0
1 changed files with 12 additions and 0 deletions
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12
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
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@ -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: