mlxsw: spectrum: Track sampling triggers in a hash table

Currently, mlxsw supports a single sampling trigger type (i.e., received
packet). When sampling is configured on an ingress port, the sampling
parameters (e.g., pointer to the psample group) are stored as an
attribute of the port, so that they could be passed to
psample_sample_packet() when a sampled packet is trapped to the CPU.

Subsequent patches are going to add more types of sampling triggers,
making it difficult to maintain the current scheme.

Instead, store all the active sampling triggers with their associated
parameters in a hash table. That way, more trigger types can be easily
added.

The next patch will flip mlxsw to use the hash table instead of the
current scheme.

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 148 insertions, 0 deletions

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
index 6054147fd51c..7e40d45b55fe 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum.c
@@ -23,6 +23,8 @@
 #include <linux/netlink.h>
 #include <linux/jhash.h>
 #include <linux/log2.h>
+#include <linux/refcount.h>
+#include <linux/rhashtable.h>
 #include <net/switchdev.h>
 #include <net/pkt_cls.h>
 #include <net/netevent.h>
@@ -2550,6 +2552,142 @@ static const struct mlxsw_sp_ptp_ops mlxsw_sp2_ptp_ops = {
 	.get_stats	= mlxsw_sp2_get_stats,
 };
 
+struct mlxsw_sp_sample_trigger_node {
+	struct mlxsw_sp_sample_trigger trigger;
+	struct mlxsw_sp_sample_params params;
+	struct rhash_head ht_node;
+	struct rcu_head rcu;
+	refcount_t refcount;
+};
+
+static const struct rhashtable_params mlxsw_sp_sample_trigger_ht_params = {
+	.key_offset = offsetof(struct mlxsw_sp_sample_trigger_node, trigger),
+	.head_offset = offsetof(struct mlxsw_sp_sample_trigger_node, ht_node),
+	.key_len = sizeof(struct mlxsw_sp_sample_trigger),
+	.automatic_shrinking = true,
+};
+
+static void
+mlxsw_sp_sample_trigger_key_init(struct mlxsw_sp_sample_trigger *key,
+				 const struct mlxsw_sp_sample_trigger *trigger)
+{
+	memset(key, 0, sizeof(*key));
+	key->type = trigger->type;
+	key->local_port = trigger->local_port;
+}
+
+/* RCU read lock must be held */
+struct mlxsw_sp_sample_params *
+mlxsw_sp_sample_trigger_params_lookup(struct mlxsw_sp *mlxsw_sp,
+				      const struct mlxsw_sp_sample_trigger *trigger)
+{
+	struct mlxsw_sp_sample_trigger_node *trigger_node;
+	struct mlxsw_sp_sample_trigger key;
+
+	mlxsw_sp_sample_trigger_key_init(&key, trigger);
+	trigger_node = rhashtable_lookup(&mlxsw_sp->sample_trigger_ht, &key,
+					 mlxsw_sp_sample_trigger_ht_params);
+	if (!trigger_node)
+		return NULL;
+
+	return &trigger_node->params;
+}
+
+static int
+mlxsw_sp_sample_trigger_node_init(struct mlxsw_sp *mlxsw_sp,
+				  const struct mlxsw_sp_sample_trigger *trigger,
+				  const struct mlxsw_sp_sample_params *params)
+{
+	struct mlxsw_sp_sample_trigger_node *trigger_node;
+	int err;
+
+	trigger_node = kzalloc(sizeof(*trigger_node), GFP_KERNEL);
+	if (!trigger_node)
+		return -ENOMEM;
+
+	trigger_node->trigger = *trigger;
+	trigger_node->params = *params;
+	refcount_set(&trigger_node->refcount, 1);
+
+	err = rhashtable_insert_fast(&mlxsw_sp->sample_trigger_ht,
+				     &trigger_node->ht_node,
+				     mlxsw_sp_sample_trigger_ht_params);
+	if (err)
+		goto err_rhashtable_insert;
+
+	return 0;
+
+err_rhashtable_insert:
+	kfree(trigger_node);
+	return err;
+}
+
+static void
+mlxsw_sp_sample_trigger_node_fini(struct mlxsw_sp *mlxsw_sp,
+				  struct mlxsw_sp_sample_trigger_node *trigger_node)
+{
+	rhashtable_remove_fast(&mlxsw_sp->sample_trigger_ht,
+			       &trigger_node->ht_node,
+			       mlxsw_sp_sample_trigger_ht_params);
+	kfree_rcu(trigger_node, rcu);
+}
+
+int
+mlxsw_sp_sample_trigger_params_set(struct mlxsw_sp *mlxsw_sp,
+				   const struct mlxsw_sp_sample_trigger *trigger,
+				   const struct mlxsw_sp_sample_params *params,
+				   struct netlink_ext_ack *extack)
+{
+	struct mlxsw_sp_sample_trigger_node *trigger_node;
+	struct mlxsw_sp_sample_trigger key;
+
+	ASSERT_RTNL();
+
+	mlxsw_sp_sample_trigger_key_init(&key, trigger);
+
+	trigger_node = rhashtable_lookup_fast(&mlxsw_sp->sample_trigger_ht,
+					      &key,
+					      mlxsw_sp_sample_trigger_ht_params);
+	if (!trigger_node)
+		return mlxsw_sp_sample_trigger_node_init(mlxsw_sp, &key,
+							 params);
+
+	if (trigger_node->params.psample_group != params->psample_group ||
+	    trigger_node->params.truncate != params->truncate ||
+	    trigger_node->params.rate != params->rate ||
+	    trigger_node->params.trunc_size != params->trunc_size) {
+		NL_SET_ERR_MSG_MOD(extack, "Sampling parameters do not match for an existing sampling trigger");
+		return -EINVAL;
+	}
+
+	refcount_inc(&trigger_node->refcount);
+
+	return 0;
+}
+
+void
+mlxsw_sp_sample_trigger_params_unset(struct mlxsw_sp *mlxsw_sp,
+				     const struct mlxsw_sp_sample_trigger *trigger)
+{
+	struct mlxsw_sp_sample_trigger_node *trigger_node;
+	struct mlxsw_sp_sample_trigger key;
+
+	ASSERT_RTNL();
+
+	mlxsw_sp_sample_trigger_key_init(&key, trigger);
+
+	trigger_node = rhashtable_lookup_fast(&mlxsw_sp->sample_trigger_ht,
+					      &key,
+					      mlxsw_sp_sample_trigger_ht_params);
+	if (!trigger_node)
+		return;
+
+	if (!refcount_dec_and_test(&trigger_node->refcount))
+		return;
+
+	mlxsw_sp_sample_trigger_node_fini(mlxsw_sp, trigger_node);
+}
+
 static int mlxsw_sp_netdevice_event(struct notifier_block *unused,
 				    unsigned long event, void *ptr);
 
@@ -2704,6 +2842,13 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 		goto err_port_module_info_init;
 	}
 
+	err = rhashtable_init(&mlxsw_sp->sample_trigger_ht,
+			      &mlxsw_sp_sample_trigger_ht_params);
+	if (err) {
+		dev_err(mlxsw_sp->bus_info->dev, "Failed to init sampling trigger hashtable\n");
+		goto err_sample_trigger_init;
+	}
+
 	err = mlxsw_sp_ports_create(mlxsw_sp);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to create ports\n");
@@ -2713,6 +2858,8 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 	return 0;
 
 err_ports_create:
+	rhashtable_destroy(&mlxsw_sp->sample_trigger_ht);
+err_sample_trigger_init:
 	mlxsw_sp_port_module_info_fini(mlxsw_sp);
 err_port_module_info_init:
 	mlxsw_sp_dpipe_fini(mlxsw_sp);
@@ -2847,6 +2994,7 @@ static void mlxsw_sp_fini(struct mlxsw_core *mlxsw_core)
 	struct mlxsw_sp *mlxsw_sp = mlxsw_core_driver_priv(mlxsw_core);
 
 	mlxsw_sp_ports_remove(mlxsw_sp);
+	rhashtable_destroy(&mlxsw_sp->sample_trigger_ht);
 	mlxsw_sp_port_module_info_fini(mlxsw_sp);
 	mlxsw_sp_dpipe_fini(mlxsw_sp);
 	unregister_netdevice_notifier_net(mlxsw_sp_net(mlxsw_sp),