netdev - [net 8/8] net/mlx5e: CT: Use rhashtable's ct entries instead of a separate list

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Date:   Wed,  8 Apr 2020 15:51:24 -0700
From:   Saeed Mahameed <saeedm@...lanox.com>
To:     "David S. Miller" <davem@...emloft.net>
Cc:     netdev@...r.kernel.org, Paul Blakey <paulb@...lanox.com>,
        Oz Shlomo <ozsh@...lanox.com>,
        Saeed Mahameed <saeedm@...lanox.com>
Subject: [net 8/8] net/mlx5e: CT: Use rhashtable's ct entries instead of a separate list

From: Paul Blakey <paulb@...lanox.com>

Fixes CT entries list corruption.

After allowing parallel insertion/removals in upper nf flow table
layer, unprotected ct entries list can be corrupted by parallel add/del
on the same flow table.

CT entries list is only used while freeing a ct zone flow table to
go over all the ct entries offloaded on that zone/table, and flush
the table.

As rhashtable already provides an api to go over all the inserted entries,
fix the race by using the rhashtable iteration instead, and remove the list.

Fixes: 7da182a998d6 ("netfilter: flowtable: Use work entry per offload command")
Reviewed-by: Oz Shlomo <ozsh@...lanox.com>
Signed-off-by: Paul Blakey <paulb@...lanox.com>
Signed-off-by: Saeed Mahameed <saeedm@...lanox.com>
---
 .../ethernet/mellanox/mlx5/core/en/tc_ct.c    | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
index ad3e3a65d403..16416eaac39e 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/tc_ct.c
@@ -67,11 +67,9 @@ struct mlx5_ct_ft {
 	struct nf_flowtable *nf_ft;
 	struct mlx5_tc_ct_priv *ct_priv;
 	struct rhashtable ct_entries_ht;
-	struct list_head ct_entries_list;
 };
 
 struct mlx5_ct_entry {
-	struct list_head list;
 	u16 zone;
 	struct rhash_head node;
 	struct flow_rule *flow_rule;
@@ -617,8 +615,6 @@ mlx5_tc_ct_block_flow_offload_add(struct mlx5_ct_ft *ft,
 	if (err)
 		goto err_insert;
 
-	list_add(&entry->list, &ft->ct_entries_list);
-
 	return 0;
 
 err_insert:
@@ -646,7 +642,6 @@ mlx5_tc_ct_block_flow_offload_del(struct mlx5_ct_ft *ft,
 	WARN_ON(rhashtable_remove_fast(&ft->ct_entries_ht,
 				       &entry->node,
 				       cts_ht_params));
-	list_del(&entry->list);
 	kfree(entry);
 
 	return 0;
@@ -818,7 +813,6 @@ mlx5_tc_ct_add_ft_cb(struct mlx5_tc_ct_priv *ct_priv, u16 zone,
 	ft->zone = zone;
 	ft->nf_ft = nf_ft;
 	ft->ct_priv = ct_priv;
-	INIT_LIST_HEAD(&ft->ct_entries_list);
 	refcount_set(&ft->refcount, 1);
 
 	err = rhashtable_init(&ft->ct_entries_ht, &cts_ht_params);
@@ -847,12 +841,12 @@ mlx5_tc_ct_add_ft_cb(struct mlx5_tc_ct_priv *ct_priv, u16 zone,
 }
 
 static void
-mlx5_tc_ct_flush_ft(struct mlx5_tc_ct_priv *ct_priv, struct mlx5_ct_ft *ft)
+mlx5_tc_ct_flush_ft_entry(void *ptr, void *arg)
 {
-	struct mlx5_ct_entry *entry;
+	struct mlx5_tc_ct_priv *ct_priv = arg;
+	struct mlx5_ct_entry *entry = ptr;
 
-	list_for_each_entry(entry, &ft->ct_entries_list, list)
-		mlx5_tc_ct_entry_del_rules(ft->ct_priv, entry);
+	mlx5_tc_ct_entry_del_rules(ct_priv, entry);
 }
 
 static void
@@ -863,9 +857,10 @@ mlx5_tc_ct_del_ft_cb(struct mlx5_tc_ct_priv *ct_priv, struct mlx5_ct_ft *ft)
 
 	nf_flow_table_offload_del_cb(ft->nf_ft,
 				     mlx5_tc_ct_block_flow_offload, ft);
-	mlx5_tc_ct_flush_ft(ct_priv, ft);
 	rhashtable_remove_fast(&ct_priv->zone_ht, &ft->node, zone_params);
-	rhashtable_destroy(&ft->ct_entries_ht);
+	rhashtable_free_and_destroy(&ft->ct_entries_ht,
+				    mlx5_tc_ct_flush_ft_entry,
+				    ct_priv);
 	kfree(ft);
 }
 
-- 
2.25.1