mlxsw: Handle config changes pertinent to SPAN

For some netdevices, for which mlxsw offloads mirroring, may have a
complex relationship between the declared intent and low-level
device configuration.

Trying to accurately track which changes might influence offloading
decisions is finicky and error-prone. Instead, this patch introduces a
function mlxsw_sp_span_entry_respin, which re-queries the configuration
anew and, if different, removes the existing offloads and installs new
ones.

Call this function strategically at event handlers that might influence
the mirroring configuration.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

 /*
  * drivers/net/ethernet/mellanox/mlxsw/spectrum.c
- * Copyright (c) 2015-2017 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2015-2018 Mellanox Technologies. All rights reserved.
  * Copyright (c) 2015-2017 Jiri Pirko <jiri@mellanox.com>
  * Copyright (c) 2015 Ido Schimmel <idosch@mellanox.com>
  * Copyright (c) 2015 Elad Raz <eladr@mellanox.com>
@@ -3667,14 +3667,24 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 		goto err_afa_init;
 	}
 
+	err = mlxsw_sp_span_init(mlxsw_sp);
+	if (err) {
+		dev_err(mlxsw_sp->bus_info->dev, "Failed to init span system\n");
+		goto err_span_init;
+	}
+
+	/* Initialize router after SPAN is initialized, so that the FIB and
+	 * neighbor event handlers can issue SPAN respin.
+	 */
 	err = mlxsw_sp_router_init(mlxsw_sp);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to initialize router\n");
 		goto err_router_init;
 	}
 
-	/* Initialize netdevice notifier after router is initialized, so that
-	 * the event handler can use router structures.
+	/* Initialize netdevice notifier after router and SPAN is initialized,
+	 * so that the event handler can use router structures and call SPAN
+	 * respin.
 	 */
 	mlxsw_sp->netdevice_nb.notifier_call = mlxsw_sp_netdevice_event;
 	err = register_netdevice_notifier(&mlxsw_sp->netdevice_nb);
@@ -3683,12 +3693,6 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 		goto err_netdev_notifier;
 	}
 
-	err = mlxsw_sp_span_init(mlxsw_sp);
-	if (err) {
-		dev_err(mlxsw_sp->bus_info->dev, "Failed to init span system\n");
-		goto err_span_init;
-	}
-
 	err = mlxsw_sp_acl_init(mlxsw_sp);
 	if (err) {
 		dev_err(mlxsw_sp->bus_info->dev, "Failed to initialize ACL\n");
@@ -3714,12 +3718,12 @@ static int mlxsw_sp_init(struct mlxsw_core *mlxsw_core,
 err_dpipe_init:
 	mlxsw_sp_acl_fini(mlxsw_sp);
 err_acl_init:
-	mlxsw_sp_span_fini(mlxsw_sp);
-err_span_init:
 	unregister_netdevice_notifier(&mlxsw_sp->netdevice_nb);
 err_netdev_notifier:
 	mlxsw_sp_router_fini(mlxsw_sp);
 err_router_init:
+	mlxsw_sp_span_fini(mlxsw_sp);
+err_span_init:
 	mlxsw_sp_afa_fini(mlxsw_sp);
 err_afa_init:
 	mlxsw_sp_counter_pool_fini(mlxsw_sp);
@@ -3745,9 +3749,9 @@ static void mlxsw_sp_fini(struct mlxsw_core *mlxsw_core)
 	mlxsw_sp_ports_remove(mlxsw_sp);
 	mlxsw_sp_dpipe_fini(mlxsw_sp);
 	mlxsw_sp_acl_fini(mlxsw_sp);
-	mlxsw_sp_span_fini(mlxsw_sp);
 	unregister_netdevice_notifier(&mlxsw_sp->netdevice_nb);
 	mlxsw_sp_router_fini(mlxsw_sp);
+	mlxsw_sp_span_fini(mlxsw_sp);
 	mlxsw_sp_afa_fini(mlxsw_sp);
 	mlxsw_sp_counter_pool_fini(mlxsw_sp);
 	mlxsw_sp_switchdev_fini(mlxsw_sp);
@@ -4641,6 +4645,7 @@ static int mlxsw_sp_netdevice_event(struct notifier_block *nb,
 		if (span_entry)
 			mlxsw_sp_span_entry_invalidate(mlxsw_sp, span_entry);
 	}
+	mlxsw_sp_span_respin(mlxsw_sp);
 
 	if (mlxsw_sp_netdev_is_ipip_ol(mlxsw_sp, dev))
 		err = mlxsw_sp_netdevice_ipip_ol_event(mlxsw_sp, dev,

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -70,6 +70,7 @@
 #include "spectrum_mr.h"
 #include "spectrum_mr_tcam.h"
 #include "spectrum_router.h"
+#include "spectrum_span.h"
 
 struct mlxsw_sp_fib;
 struct mlxsw_sp_vr;
@@ -2330,6 +2331,8 @@ static void mlxsw_sp_router_neigh_event_work(struct work_struct *work)
 	read_unlock_bh(&n->lock);
 
 	rtnl_lock();
+	mlxsw_sp_span_respin(mlxsw_sp);
+
 	entry_connected = nud_state & NUD_VALID && !dead;
 	neigh_entry = mlxsw_sp_neigh_entry_lookup(mlxsw_sp, n);
 	if (!entry_connected && !neigh_entry)
@@ -5589,6 +5592,8 @@ static void mlxsw_sp_router_fib4_event_work(struct work_struct *work)
 
 	/* Protect internal structures from changes */
 	rtnl_lock();
+	mlxsw_sp_span_respin(mlxsw_sp);
+
 	switch (fib_work->event) {
 	case FIB_EVENT_ENTRY_REPLACE: /* fall through */
 	case FIB_EVENT_ENTRY_APPEND: /* fall through */
@@ -5631,6 +5636,8 @@ static void mlxsw_sp_router_fib6_event_work(struct work_struct *work)
 	int err;
 
 	rtnl_lock();
+	mlxsw_sp_span_respin(mlxsw_sp);
+
 	switch (fib_work->event) {
 	case FIB_EVENT_ENTRY_REPLACE: /* fall through */
 	case FIB_EVENT_ENTRY_ADD:

drivers/net/ethernet/mellanox/mlxsw/spectrum_span.c

@@ -502,3 +502,27 @@ void mlxsw_sp_span_mirror_del(struct mlxsw_sp_port *from, int span_id,
 		   span_entry->id);
 	mlxsw_sp_span_inspected_port_del(from, span_entry, type, bind);
 }
+
+void mlxsw_sp_span_respin(struct mlxsw_sp *mlxsw_sp)
+{
+	int i;
+	int err;
+
+	ASSERT_RTNL();
+	for (i = 0; i < mlxsw_sp->span.entries_count; i++) {
+		struct mlxsw_sp_span_entry *curr = &mlxsw_sp->span.entries[i];
+		struct mlxsw_sp_span_parms sparms = {0};
+
+		if (!curr->ref_count)
+			continue;
+
+		err = curr->ops->parms(curr->to_dev, &sparms);
+		if (err)
+			continue;
+
+		if (memcmp(&sparms, &curr->parms, sizeof(sparms))) {
+			mlxsw_sp_span_entry_deconfigure(curr);
+			mlxsw_sp_span_entry_configure(mlxsw_sp, curr, sparms);
+		}
+	}
+}

drivers/net/ethernet/mellanox/mlxsw/spectrum_span.h

@@ -76,6 +76,7 @@ struct mlxsw_sp_span_entry_ops {
 
 int mlxsw_sp_span_init(struct mlxsw_sp *mlxsw_sp);
 void mlxsw_sp_span_fini(struct mlxsw_sp *mlxsw_sp);
+void mlxsw_sp_span_respin(struct mlxsw_sp *mlxsw_sp);
 
 int mlxsw_sp_span_mirror_add(struct mlxsw_sp_port *from,
 			     const struct net_device *to_dev,