net/mlx5: DR, Improve steering for empty or RX/TX-only matchers

Every matcher has RX and TX paths. When a new matcher is created, its RX
and TX start/end anchors are connected to the respective RX and TX anchors
of the previous and next matchers.
This creates a potential performance issue: when a certain rule is added
to a matcher, in many cases it is RX or TX only rule, which may create a
long chain of RX/TX-only paths w/o the actual rules.

This patch aims to handle this issue.

RX and TX matchers are now handled separately: matcher connection in the
matchers chain is split into two separate lists: RX only and TX only.
when a new matcher is created, it is initially created 'detached' - its
RX/TX members are not inserted into the table's matcher list.
When an actual rule is added, only its appropriate RX or TX nic matchers
are then added to the table's nic matchers list and inserted into its
place in the chain of matchers.
I.e., if the rule that is being added is an RX-only rule, only the RX
part of the matcher will be connected to the chain, while TX part of the
matcher remains detached and doesn't prolong the TX chain of the matchers.

Same goes for rule deletion: when the last RX/TX rule of the nic matcher
is destroyed, the nic matcher is removed from its list.

Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>

1 files changed, 25 insertions, 3 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
index 43e7fe85cbc7..b4374578425b 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
@@ -990,8 +990,20 @@ static bool dr_rule_verify(struct mlx5dr_matcher *matcher,
 static int dr_rule_destroy_rule_nic(struct mlx5dr_rule *rule,
 				    struct mlx5dr_rule_rx_tx *nic_rule)
 {
+	/* Check if this nic rule was actually created, or was it skipped
+	 * and only the other type of the RX/TX nic rule was created.
+	 */
+	if (!nic_rule->last_rule_ste)
+		return 0;
+
 	mlx5dr_domain_nic_lock(nic_rule->nic_matcher->nic_tbl->nic_dmn);
 	dr_rule_clean_rule_members(rule, nic_rule);
+
+	nic_rule->nic_matcher->rules--;
+	if (!nic_rule->nic_matcher->rules)
+		mlx5dr_matcher_remove_from_tbl_nic(rule->matcher->tbl->dmn,
+						   nic_rule->nic_matcher);
+
 	mlx5dr_domain_nic_unlock(nic_rule->nic_matcher->nic_tbl->nic_dmn);
 
 	return 0;
@@ -1098,24 +1110,28 @@ dr_rule_create_rule_nic(struct mlx5dr_rule *rule,
 
 	mlx5dr_domain_nic_lock(nic_dmn);
 
+	ret = mlx5dr_matcher_add_to_tbl_nic(dmn, nic_matcher);
+	if (ret)
+		goto free_hw_ste;
+
 	ret = mlx5dr_matcher_select_builders(matcher,
 					     nic_matcher,
 					     dr_rule_get_ipv(&param->outer),
 					     dr_rule_get_ipv(&param->inner));
 	if (ret)
-		goto free_hw_ste;
+		goto remove_from_nic_tbl;
 
 	/* Set the tag values inside the ste array */
 	ret = mlx5dr_ste_build_ste_arr(matcher, nic_matcher, param, hw_ste_arr);
 	if (ret)
-		goto free_hw_ste;
+		goto remove_from_nic_tbl;
 
 	/* Set the actions values/addresses inside the ste array */
 	ret = mlx5dr_actions_build_ste_arr(matcher, nic_matcher, actions,
 					   num_actions, hw_ste_arr,
 					   &new_hw_ste_arr_sz);
 	if (ret)
-		goto free_hw_ste;
+		goto remove_from_nic_tbl;
 
 	cur_htbl = nic_matcher->s_htbl;
 
@@ -1162,6 +1178,8 @@ dr_rule_create_rule_nic(struct mlx5dr_rule *rule,
 	if (htbl)
 		mlx5dr_htbl_put(htbl);
 
+	nic_matcher->rules++;
+
 	mlx5dr_domain_nic_unlock(nic_dmn);
 
 	kfree(hw_ste_arr);
@@ -1175,6 +1193,10 @@ free_rule:
 		list_del(&ste_info->send_list);
 		kfree(ste_info);
 	}
+
+remove_from_nic_tbl:
+	mlx5dr_matcher_remove_from_tbl_nic(dmn, nic_matcher);
+
 free_hw_ste:
 	mlx5dr_domain_nic_unlock(nic_dmn);
 	kfree(hw_ste_arr);