nfp: flower: ignore duplicate merge hints from FW

A merge hint message needs some time to process before the merged
flow actually reaches the firmware, during which we may get duplicate
merge hints if there're more than one packet that hit the pre-merged
flow. And processing duplicate merge hints will cost extra host_ctx's
which are a limited resource.

Avoid the duplicate merge by using hash table to store the sub_flows
to be merged.

Fixes: 8af56f40e53b ("nfp: flower: offload merge flows")
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 46 insertions, 2 deletions

diff --git a/drivers/net/ethernet/netronome/nfp/flower/offload.c b/drivers/net/ethernet/netronome/nfp/flower/offload.c
index d72225d64a75..e95969c462e4 100644
--- a/drivers/net/ethernet/netronome/nfp/flower/offload.c
+++ b/drivers/net/ethernet/netronome/nfp/flower/offload.c
@@ -1009,6 +1009,8 @@ int nfp_flower_merge_offloaded_flows(struct nfp_app *app,
 	struct netlink_ext_ack *extack = NULL;
 	struct nfp_fl_payload *merge_flow;
 	struct nfp_fl_key_ls merge_key_ls;
+	struct nfp_merge_info *merge_info;
+	u64 parent_ctx = 0;
 	int err;
 
 	ASSERT_RTNL();
@@ -1019,6 +1021,15 @@ int nfp_flower_merge_offloaded_flows(struct nfp_app *app,
 	    nfp_flower_is_merge_flow(sub_flow2))
 		return -EINVAL;
 
+	/* check if the two flows are already merged */
+	parent_ctx = (u64)(be32_to_cpu(sub_flow1->meta.host_ctx_id)) << 32;
+	parent_ctx |= (u64)(be32_to_cpu(sub_flow2->meta.host_ctx_id));
+	if (rhashtable_lookup_fast(&priv->merge_table,
+				   &parent_ctx, merge_table_params)) {
+		nfp_flower_cmsg_warn(app, "The two flows are already merged.\n");
+		return 0;
+	}
+
 	err = nfp_flower_can_merge(sub_flow1, sub_flow2);
 	if (err)
 		return err;
@@ -1060,16 +1071,33 @@ int nfp_flower_merge_offloaded_flows(struct nfp_app *app,
 	if (err)
 		goto err_release_metadata;
 
+	merge_info = kmalloc(sizeof(*merge_info), GFP_KERNEL);
+	if (!merge_info) {
+		err = -ENOMEM;
+		goto err_remove_rhash;
+	}
+	merge_info->parent_ctx = parent_ctx;
+	err = rhashtable_insert_fast(&priv->merge_table, &merge_info->ht_node,
+				     merge_table_params);
+	if (err)
+		goto err_destroy_merge_info;
+
 	err = nfp_flower_xmit_flow(app, merge_flow,
 				   NFP_FLOWER_CMSG_TYPE_FLOW_MOD);
 	if (err)
-		goto err_remove_rhash;
+		goto err_remove_merge_info;
 
 	merge_flow->in_hw = true;
 	sub_flow1->in_hw = false;
 
 	return 0;
 
+err_remove_merge_info:
+	WARN_ON_ONCE(rhashtable_remove_fast(&priv->merge_table,
+					    &merge_info->ht_node,
+					    merge_table_params));
+err_destroy_merge_info:
+	kfree(merge_info);
 err_remove_rhash:
 	WARN_ON_ONCE(rhashtable_remove_fast(&priv->flow_table,
 					    &merge_flow->fl_node,
@@ -1359,7 +1387,9 @@ nfp_flower_remove_merge_flow(struct nfp_app *app,
 {
 	struct nfp_flower_priv *priv = app->priv;
 	struct nfp_fl_payload_link *link, *temp;
+	struct nfp_merge_info *merge_info;
 	struct nfp_fl_payload *origin;
+	u64 parent_ctx = 0;
 	bool mod = false;
 	int err;
 
@@ -1396,8 +1426,22 @@ nfp_flower_remove_merge_flow(struct nfp_app *app,
 err_free_links:
 	/* Clean any links connected with the merged flow. */
 	list_for_each_entry_safe(link, temp, &merge_flow->linked_flows,
-				 merge_flow.list)
+				 merge_flow.list) {
+		u32 ctx_id = be32_to_cpu(link->sub_flow.flow->meta.host_ctx_id);
+
+		parent_ctx = (parent_ctx << 32) | (u64)(ctx_id);
 		nfp_flower_unlink_flow(link);
+	}
+
+	merge_info = rhashtable_lookup_fast(&priv->merge_table,
+					    &parent_ctx,
+					    merge_table_params);
+	if (merge_info) {
+		WARN_ON_ONCE(rhashtable_remove_fast(&priv->merge_table,
+						    &merge_info->ht_node,
+						    merge_table_params));
+		kfree(merge_info);
+	}
 
 	kfree(merge_flow->action_data);
 	kfree(merge_flow->mask_data);