bonding: Simplify the xmit function for modes that use xmit_hash

Earlier change to use usable slave array for TLB mode had an additional
performance advantage. So extending the same logic to all other modes
that use xmit-hash for slave selection (viz 802.3AD, and XOR modes).
Also consolidating this with the earlier TLB change.

The main idea is to build the usable slaves array in the control path
and use that array for slave selection during xmit operation.

Measured performance in a setup with a bond of 4x1G NICs with 200
instances of netperf for the modes involved (3ad, xor, tlb)
cmd: netperf -t TCP_RR -H <TargetHost> -l 60 -s 5

Mode        TPS-Before   TPS-After

802.3ad   : 468,694      493,101
TLB (lb=0): 392,583      392,965
XOR       : 475,696      484,517

Signed-off-by: Mahesh Bandewar <maheshb@google.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: Mahesh Bandewar

drivers/net/bonding/bond_3ad.c

@@ -102,17 +102,20 @@ static const u8 lacpdu_mcast_addr[ETH_ALEN] = MULTICAST_LACPDU_ADDR;
 /* ================= main 802.3ad protocol functions ================== */
 static int ad_lacpdu_send(struct port *port);
 static int ad_marker_send(struct port *port, struct bond_marker *marker);
-static void ad_mux_machine(struct port *port);
+static void ad_mux_machine(struct port *port, bool *update_slave_arr);
 static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port);
 static void ad_tx_machine(struct port *port);
 static void ad_periodic_machine(struct port *port);
-static void ad_port_selection_logic(struct port *port);
-static void ad_agg_selection_logic(struct aggregator *aggregator);
+static void ad_port_selection_logic(struct port *port, bool *update_slave_arr);
+static void ad_agg_selection_logic(struct aggregator *aggregator,
+				   bool *update_slave_arr);
 static void ad_clear_agg(struct aggregator *aggregator);
 static void ad_initialize_agg(struct aggregator *aggregator);
 static void ad_initialize_port(struct port *port, int lacp_fast);
-static void ad_enable_collecting_distributing(struct port *port);
-static void ad_disable_collecting_distributing(struct port *port);
+static void ad_enable_collecting_distributing(struct port *port,
+					      bool *update_slave_arr);
+static void ad_disable_collecting_distributing(struct port *port,
+					       bool *update_slave_arr);
 static void ad_marker_info_received(struct bond_marker *marker_info,
 				    struct port *port);
 static void ad_marker_response_received(struct bond_marker *marker,
@@ -796,8 +799,9 @@ static int ad_marker_send(struct port *port, struct bond_marker *marker)
 /**
  * ad_mux_machine - handle a port's mux state machine
  * @port: the port we're looking at
+ * @update_slave_arr: Does slave array need update?
  */
-static void ad_mux_machine(struct port *port)
+static void ad_mux_machine(struct port *port, bool *update_slave_arr)
 {
 	mux_states_t last_state;
 
@@ -901,7 +905,8 @@ static void ad_mux_machine(struct port *port)
 		switch (port->sm_mux_state) {
 		case AD_MUX_DETACHED:
 			port->actor_oper_port_state &= ~AD_STATE_SYNCHRONIZATION;
-			ad_disable_collecting_distributing(port);
+			ad_disable_collecting_distributing(port,
+							   update_slave_arr);
 			port->actor_oper_port_state &= ~AD_STATE_COLLECTING;
 			port->actor_oper_port_state &= ~AD_STATE_DISTRIBUTING;
 			port->ntt = true;
@@ -913,13 +918,15 @@ static void ad_mux_machine(struct port *port)
 			port->actor_oper_port_state |= AD_STATE_SYNCHRONIZATION;
 			port->actor_oper_port_state &= ~AD_STATE_COLLECTING;
 			port->actor_oper_port_state &= ~AD_STATE_DISTRIBUTING;
-			ad_disable_collecting_distributing(port);
+			ad_disable_collecting_distributing(port,
+							   update_slave_arr);
 			port->ntt = true;
 			break;
 		case AD_MUX_COLLECTING_DISTRIBUTING:
 			port->actor_oper_port_state |= AD_STATE_COLLECTING;
 			port->actor_oper_port_state |= AD_STATE_DISTRIBUTING;
-			ad_enable_collecting_distributing(port);
+			ad_enable_collecting_distributing(port,
+							  update_slave_arr);
 			port->ntt = true;
 			break;
 		default:
@@ -1187,12 +1194,13 @@ static void ad_periodic_machine(struct port *port)
 /**
  * ad_port_selection_logic - select aggregation groups
  * @port: the port we're looking at
+ * @update_slave_arr: Does slave array need update?
  *
  * Select aggregation groups, and assign each port for it's aggregetor. The
  * selection logic is called in the inititalization (after all the handshkes),
  * and after every lacpdu receive (if selected is off).
  */
-static void ad_port_selection_logic(struct port *port)
+static void ad_port_selection_logic(struct port *port, bool *update_slave_arr)
 {
 	struct aggregator *aggregator, *free_aggregator = NULL, *temp_aggregator;
 	struct port *last_port = NULL, *curr_port;
@@ -1347,7 +1355,7 @@ static void ad_port_selection_logic(struct port *port)
 			      __agg_ports_are_ready(port->aggregator));
 
 	aggregator = __get_first_agg(port);
-	ad_agg_selection_logic(aggregator);
+	ad_agg_selection_logic(aggregator, update_slave_arr);
 }
 
 /* Decide if "agg" is a better choice for the new active aggregator that
@@ -1435,6 +1443,7 @@ static int agg_device_up(const struct aggregator *agg)
 /**
  * ad_agg_selection_logic - select an aggregation group for a team
  * @aggregator: the aggregator we're looking at
+ * @update_slave_arr: Does slave array need update?
  *
  * It is assumed that only one aggregator may be selected for a team.
  *
@@ -1457,7 +1466,8 @@ static int agg_device_up(const struct aggregator *agg)
  * __get_active_agg() won't work correctly. This function should be better
  * called with the bond itself, and retrieve the first agg from it.
  */
-static void ad_agg_selection_logic(struct aggregator *agg)
+static void ad_agg_selection_logic(struct aggregator *agg,
+				   bool *update_slave_arr)
 {
 	struct aggregator *best, *active, *origin;
 	struct bonding *bond = agg->slave->bond;
@@ -1550,6 +1560,8 @@ static void ad_agg_selection_logic(struct aggregator *agg)
 				__disable_port(port);
 			}
 		}
+		/* Slave array needs update. */
+		*update_slave_arr = true;
 	}
 
 	/* if the selected aggregator is of join individuals
@@ -1678,24 +1690,30 @@ static void ad_initialize_port(struct port *port, int lacp_fast)
 /**
  * ad_enable_collecting_distributing - enable a port's transmit/receive
  * @port: the port we're looking at
+ * @update_slave_arr: Does slave array need update?
  *
  * Enable @port if it's in an active aggregator
  */
-static void ad_enable_collecting_distributing(struct port *port)
+static void ad_enable_collecting_distributing(struct port *port,
+					      bool *update_slave_arr)
 {
 	if (port->aggregator->is_active) {
 		pr_debug("Enabling port %d(LAG %d)\n",
 			 port->actor_port_number,
 			 port->aggregator->aggregator_identifier);
 		__enable_port(port);
+		/* Slave array needs update */
+		*update_slave_arr = true;
 	}
 }
 
 /**
  * ad_disable_collecting_distributing - disable a port's transmit/receive
  * @port: the port we're looking at
+ * @update_slave_arr: Does slave array need update?
  */
-static void ad_disable_collecting_distributing(struct port *port)
+static void ad_disable_collecting_distributing(struct port *port,
+					       bool *update_slave_arr)
 {
 	if (port->aggregator &&
 	    !MAC_ADDRESS_EQUAL(&(port->aggregator->partner_system),
@@ -1704,6 +1722,8 @@ static void ad_disable_collecting_distributing(struct port *port)
 			 port->actor_port_number,
 			 port->aggregator->aggregator_identifier);
 		__disable_port(port);
+		/* Slave array needs an update */
+		*update_slave_arr = true;
 	}
 }
 
@@ -1868,6 +1888,7 @@ void bond_3ad_unbind_slave(struct slave *slave)
 	struct bonding *bond = slave->bond;
 	struct slave *slave_iter;
 	struct list_head *iter;
+	bool dummy_slave_update; /* Ignore this value as caller updates array */
 
 	/* Sync against bond_3ad_state_machine_handler() */
 	spin_lock_bh(&bond->mode_lock);
@@ -1951,7 +1972,8 @@ void bond_3ad_unbind_slave(struct slave *slave)
 				ad_clear_agg(aggregator);
 
 				if (select_new_active_agg)
-					ad_agg_selection_logic(__get_first_agg(port));
+					ad_agg_selection_logic(__get_first_agg(port),
+							       &dummy_slave_update);
 			} else {
 				netdev_warn(bond->dev, "unbinding aggregator, and could not find a new aggregator for its ports\n");
 			}
@@ -1966,7 +1988,8 @@ void bond_3ad_unbind_slave(struct slave *slave)
 				/* select new active aggregator */
 				temp_aggregator = __get_first_agg(port);
 				if (temp_aggregator)
-					ad_agg_selection_logic(temp_aggregator);
+					ad_agg_selection_logic(temp_aggregator,
+							       &dummy_slave_update);
 			}
 		}
 	}
@@ -1996,7 +2019,8 @@ void bond_3ad_unbind_slave(struct slave *slave)
 					if (select_new_active_agg) {
 						netdev_info(bond->dev, "Removing an active aggregator\n");
 						/* select new active aggregator */
-						ad_agg_selection_logic(__get_first_agg(port));
+						ad_agg_selection_logic(__get_first_agg(port),
+							               &dummy_slave_update);
 					}
 				}
 				break;
@@ -2031,6 +2055,7 @@ void bond_3ad_state_machine_handler(struct work_struct *work)
 	struct slave *slave;
 	struct port *port;
 	bool should_notify_rtnl = BOND_SLAVE_NOTIFY_LATER;
+	bool update_slave_arr = false;
 
 	/* Lock to protect data accessed by all (e.g., port->sm_vars) and
 	 * against running with bond_3ad_unbind_slave. ad_rx_machine may run
@@ -2058,7 +2083,7 @@ void bond_3ad_state_machine_handler(struct work_struct *work)
 			}
 
 			aggregator = __get_first_agg(port);
-			ad_agg_selection_logic(aggregator);
+			ad_agg_selection_logic(aggregator, &update_slave_arr);
 		}
 		bond_3ad_set_carrier(bond);
 	}
@@ -2074,8 +2099,8 @@ void bond_3ad_state_machine_handler(struct work_struct *work)
 
 		ad_rx_machine(NULL, port);
 		ad_periodic_machine(port);
-		ad_port_selection_logic(port);
-		ad_mux_machine(port);
+		ad_port_selection_logic(port, &update_slave_arr);
+		ad_mux_machine(port, &update_slave_arr);
 		ad_tx_machine(port);
 
 		/* turn off the BEGIN bit, since we already handled it */
@@ -2093,6 +2118,9 @@ void bond_3ad_state_machine_handler(struct work_struct *work)
 	rcu_read_unlock();
 	spin_unlock_bh(&bond->mode_lock);
 
+	if (update_slave_arr)
+		bond_slave_arr_work_rearm(bond, 0);
+
 	if (should_notify_rtnl && rtnl_trylock()) {
 		bond_slave_state_notify(bond);
 		rtnl_unlock();
@@ -2283,6 +2311,11 @@ void bond_3ad_handle_link_change(struct slave *slave, char link)
 	port->sm_vars |= AD_PORT_BEGIN;
 
 	spin_unlock_bh(&slave->bond->mode_lock);
+
+	/* RTNL is held and mode_lock is released so it's safe
+	 * to update slave_array here.
+	 */
+	bond_update_slave_arr(slave->bond, NULL);
 }
 
 /**
@@ -2377,73 +2410,6 @@ int bond_3ad_get_active_agg_info(struct bonding *bond, struct ad_info *ad_info)
 	return ret;
 }
 
-int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
-{
-	struct bonding *bond = netdev_priv(dev);
-	struct slave *slave, *first_ok_slave;
-	struct aggregator *agg;
-	struct ad_info ad_info;
-	struct list_head *iter;
-	int slaves_in_agg;
-	int slave_agg_no;
-	int agg_id;
-
-	if (__bond_3ad_get_active_agg_info(bond, &ad_info)) {
-		netdev_dbg(dev, "__bond_3ad_get_active_agg_info failed\n");
-		goto err_free;
-	}
-
-	slaves_in_agg = ad_info.ports;
-	agg_id = ad_info.aggregator_id;
-
-	if (slaves_in_agg == 0) {
-		netdev_dbg(dev, "active aggregator is empty\n");
-		goto err_free;
-	}
-
-	slave_agg_no = bond_xmit_hash(bond, skb) % slaves_in_agg;
-	first_ok_slave = NULL;
-
-	bond_for_each_slave_rcu(bond, slave, iter) {
-		agg = SLAVE_AD_INFO(slave)->port.aggregator;
-		if (!agg || agg->aggregator_identifier != agg_id)
-			continue;
-
-		if (slave_agg_no >= 0) {
-			if (!first_ok_slave && bond_slave_can_tx(slave))
-				first_ok_slave = slave;
-			slave_agg_no--;
-			continue;
-		}
-
-		if (bond_slave_can_tx(slave)) {
-			bond_dev_queue_xmit(bond, skb, slave->dev);
-			goto out;
-		}
-	}
-
-	if (slave_agg_no >= 0) {
-		netdev_err(dev, "Couldn't find a slave to tx on for aggregator ID %d\n",
-			   agg_id);
-		goto err_free;
-	}
-
-	/* we couldn't find any suitable slave after the agg_no, so use the
-	 * first suitable found, if found.
-	 */
-	if (first_ok_slave)
-		bond_dev_queue_xmit(bond, skb, first_ok_slave->dev);
-	else
-		goto err_free;
-
-out:
-	return NETDEV_TX_OK;
-err_free:
-	/* no suitable interface, frame not sent */
-	dev_kfree_skb_any(skb);
-	goto out;
-}
-
 int bond_3ad_lacpdu_recv(const struct sk_buff *skb, struct bonding *bond,
 			 struct slave *slave)
 {