sfc: add a hashtable for offloaded TC rules

Nothing inserts into this table yet, but we have code to remove rules
 on FLOW_CLS_DESTROY or at driver teardown time, in both cases also
 attempting to remove the corresponding hardware rules.
Signed-off-by: Edward Cree <ecree.xilinx@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/ef100_rep.c

@@ -135,7 +135,7 @@ static void efx_ef100_rep_get_stats64(struct net_device *dev,
 	stats->tx_errors = atomic64_read(&efv->stats.tx_errors);
 }
 
-static const struct net_device_ops efx_ef100_rep_netdev_ops = {
+const struct net_device_ops efx_ef100_rep_netdev_ops = {
 	.ndo_open		= efx_ef100_rep_open,
 	.ndo_stop		= efx_ef100_rep_close,
 	.ndo_start_xmit		= efx_ef100_rep_xmit,

drivers/net/ethernet/sfc/ef100_rep.h

@@ -66,4 +66,5 @@ void efx_ef100_rep_rx_packet(struct efx_rep *efv, struct efx_rx_buffer *rx_buf);
  * Caller must hold rcu_read_lock().
  */
 struct efx_rep *efx_ef100_find_rep_by_mport(struct efx_nic *efx, u16 mport);
+extern const struct net_device_ops efx_ef100_rep_netdev_ops;
 #endif /* EF100_REP_H */

drivers/net/ethernet/sfc/tc.c

@@ -15,6 +15,39 @@
 #include "ef100_rep.h"
 #include "efx.h"
 
+#define EFX_EFV_PF	NULL
+/* Look up the representor information (efv) for a device.
+ * May return NULL for the PF (us), or an error pointer for a device that
+ * isn't supported as a TC offload endpoint
+ */
+static struct efx_rep *efx_tc_flower_lookup_efv(struct efx_nic *efx,
+						struct net_device *dev)
+{
+	struct efx_rep *efv;
+
+	if (!dev)
+		return ERR_PTR(-EOPNOTSUPP);
+	/* Is it us (the PF)? */
+	if (dev == efx->net_dev)
+		return EFX_EFV_PF;
+	/* Is it an efx vfrep at all? */
+	if (dev->netdev_ops != &efx_ef100_rep_netdev_ops)
+		return ERR_PTR(-EOPNOTSUPP);
+	/* Is it ours?  We don't support TC rules that include another
+	 * EF100's netdevices (not even on another port of the same NIC).
+	 */
+	efv = netdev_priv(dev);
+	if (efv->parent != efx)
+		return ERR_PTR(-EOPNOTSUPP);
+	return efv;
+}
+
+static const struct rhashtable_params efx_tc_match_action_ht_params = {
+	.key_len	= sizeof(unsigned long),
+	.key_offset	= offsetof(struct efx_tc_flow_rule, cookie),
+	.head_offset	= offsetof(struct efx_tc_flow_rule, linkage),
+};
+
 static void efx_tc_free_action_set(struct efx_nic *efx,
 				   struct efx_tc_action_set *act, bool in_hw)
 {
@@ -59,10 +92,74 @@ static void efx_tc_delete_rule(struct efx_nic *efx, struct efx_tc_flow_rule *rul
 	rule->fw_id = MC_CMD_MAE_ACTION_RULE_INSERT_OUT_ACTION_RULE_ID_NULL;
 }
 
+static void efx_tc_flow_free(void *ptr, void *arg)
+{
+	struct efx_tc_flow_rule *rule = ptr;
+	struct efx_nic *efx = arg;
+
+	netif_err(efx, drv, efx->net_dev,
+		  "tc rule %lx still present at teardown, removing\n",
+		  rule->cookie);
+
+	efx_mae_delete_rule(efx, rule->fw_id);
+
+	/* Release entries in subsidiary tables */
+	efx_tc_free_action_set_list(efx, &rule->acts, true);
+
+	kfree(rule);
+}
+
+static int efx_tc_flower_destroy(struct efx_nic *efx,
+				 struct net_device *net_dev,
+				 struct flow_cls_offload *tc)
+{
+	struct netlink_ext_ack *extack = tc->common.extack;
+	struct efx_tc_flow_rule *rule;
+
+	rule = rhashtable_lookup_fast(&efx->tc->match_action_ht, &tc->cookie,
+				      efx_tc_match_action_ht_params);
+	if (!rule) {
+		/* Only log a message if we're the ingress device.  Otherwise
+		 * it's a foreign filter and we might just not have been
+		 * interested (e.g. we might not have been the egress device
+		 * either).
+		 */
+		if (!IS_ERR(efx_tc_flower_lookup_efv(efx, net_dev)))
+			netif_warn(efx, drv, efx->net_dev,
+				   "Filter %lx not found to remove\n", tc->cookie);
+		NL_SET_ERR_MSG_MOD(extack, "Flow cookie not found in offloaded rules");
+		return -ENOENT;
+	}
+
+	/* Remove it from HW */
+	efx_tc_delete_rule(efx, rule);
+	/* Delete it from SW */
+	rhashtable_remove_fast(&efx->tc->match_action_ht, &rule->linkage,
+			       efx_tc_match_action_ht_params);
+	netif_dbg(efx, drv, efx->net_dev, "Removed filter %lx\n", rule->cookie);
+	kfree(rule);
+	return 0;
+}
+
 int efx_tc_flower(struct efx_nic *efx, struct net_device *net_dev,
 		  struct flow_cls_offload *tc, struct efx_rep *efv)
 {
-	return -EOPNOTSUPP;
+	int rc;
+
+	if (!efx->tc)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&efx->tc->mutex);
+	switch (tc->command) {
+	case FLOW_CLS_DESTROY:
+		rc = efx_tc_flower_destroy(efx, net_dev, tc);
+		break;
+	default:
+		rc = -EOPNOTSUPP;
+		break;
+	}
+	mutex_unlock(&efx->tc->mutex);
+	return rc;
 }
 
 static int efx_tc_configure_default_rule(struct efx_nic *efx, u32 ing_port,
@@ -239,6 +336,8 @@ void efx_fini_tc(struct efx_nic *efx)
 
 int efx_init_struct_tc(struct efx_nic *efx)
 {
+	int rc;
+
 	if (efx->type->is_vf)
 		return 0;
 
@@ -247,6 +346,10 @@ int efx_init_struct_tc(struct efx_nic *efx)
 		return -ENOMEM;
 	INIT_LIST_HEAD(&efx->tc->block_list);
 
+	mutex_init(&efx->tc->mutex);
+	rc = rhashtable_init(&efx->tc->match_action_ht, &efx_tc_match_action_ht_params);
+	if (rc < 0)
+		goto fail_match_action_ht;
 	efx->tc->reps_filter_uc = -1;
 	efx->tc->reps_filter_mc = -1;
 	INIT_LIST_HEAD(&efx->tc->dflt.pf.acts.list);
@@ -254,6 +357,11 @@ int efx_init_struct_tc(struct efx_nic *efx)
 	INIT_LIST_HEAD(&efx->tc->dflt.wire.acts.list);
 	efx->tc->dflt.wire.fw_id = MC_CMD_MAE_ACTION_RULE_INSERT_OUT_ACTION_RULE_ID_NULL;
 	return 0;
+fail_match_action_ht:
+	mutex_destroy(&efx->tc->mutex);
+	kfree(efx->tc);
+	efx->tc = NULL;
+	return rc;
 }
 
 void efx_fini_struct_tc(struct efx_nic *efx)
@@ -261,10 +369,15 @@ void efx_fini_struct_tc(struct efx_nic *efx)
 	if (!efx->tc)
 		return;
 
+	mutex_lock(&efx->tc->mutex);
 	EFX_WARN_ON_PARANOID(efx->tc->dflt.pf.fw_id !=
 			     MC_CMD_MAE_ACTION_RULE_INSERT_OUT_ACTION_RULE_ID_NULL);
 	EFX_WARN_ON_PARANOID(efx->tc->dflt.wire.fw_id !=
 			     MC_CMD_MAE_ACTION_RULE_INSERT_OUT_ACTION_RULE_ID_NULL);
+	rhashtable_free_and_destroy(&efx->tc->match_action_ht, efx_tc_flow_free,
+				    efx);
+	mutex_unlock(&efx->tc->mutex);
+	mutex_destroy(&efx->tc->mutex);
 	kfree(efx->tc);
 	efx->tc = NULL;
 }

drivers/net/ethernet/sfc/tc.h

@@ -12,6 +12,7 @@
 #ifndef EFX_TC_H
 #define EFX_TC_H
 #include <net/flow_offload.h>
+#include <linux/rhashtable.h>
 #include "net_driver.h"
 
 /* Error reporting: convenience macros.  For indicating why a given filter
@@ -55,6 +56,8 @@ struct efx_tc_action_set_list {
 };
 
 struct efx_tc_flow_rule {
+	unsigned long cookie;
+	struct rhash_head linkage;
 	struct efx_tc_match match;
 	struct efx_tc_action_set_list acts;
 	u32 fw_id;
@@ -69,6 +72,8 @@ enum efx_tc_rule_prios {
  * struct efx_tc_state - control plane data for TC offload
  *
  * @block_list: List of &struct efx_tc_block_binding
+ * @mutex: Used to serialise operations on TC hashtables
+ * @match_action_ht: Hashtable of TC match-action rules
  * @reps_mport_id: MAE port allocated for representor RX
  * @reps_filter_uc: VNIC filter for representor unicast RX (promisc)
  * @reps_filter_mc: VNIC filter for representor multicast RX (allmulti)
@@ -81,6 +86,8 @@ enum efx_tc_rule_prios {
  */
 struct efx_tc_state {
 	struct list_head block_list;
+	struct mutex mutex;
+	struct rhashtable match_action_ht;
 	u32 reps_mport_id, reps_mport_vport_id;
 	s32 reps_filter_uc, reps_filter_mc;
 	struct {