mlxsw: spectrum_router: Track next hops at CRIFs

Move the list of next hops from struct mlxsw_sp_rif to mlxsw_sp_crif. The
reason is that eventually, next hops for mlxsw uppers should be offloaded
and unoffloaded on demand as a netdevice becomes an upper, or stops being
one. Currently, next hops are tracked at RIFs, but RIFs do not exist when a
netdevice is not an mlxsw uppers. CRIFs are kept track of throughout the
netdevice lifetime.

Correspondingly, track at each next hop not its RIF, but its CRIF (from
which a RIF can always be deduced).

Note that now that next hops are tracked at a CRIF, it is not necessary to
move each over to a new RIF when it is necessary to edit a RIF. Therefore
drop mlxsw_sp_nexthop_rif_migrate() and have mlxsw_sp_rif_migrate_destroy()
call mlxsw_sp_nexthop_rif_update() directly.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Link: https://lore.kernel.org/r/e7c1c0a7dd13883b0f09aeda12c4fcf4d63a70e3.1687438411.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: pmachata

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

@@ -59,6 +59,7 @@ struct mlxsw_sp_crif {
 	struct mlxsw_sp_crif_key key;
 	struct rhash_head ht_node;
 	bool can_destroy;
+	struct list_head nexthop_list;
 	struct mlxsw_sp_rif *rif;
 };
 
@@ -70,7 +71,6 @@ static const struct rhashtable_params mlxsw_sp_crif_ht_params = {
 
 struct mlxsw_sp_rif {
 	struct mlxsw_sp_crif *crif; /* NULL for underlay RIF */
-	struct list_head nexthop_list;
 	struct list_head neigh_list;
 	struct mlxsw_sp_fid *fid;
 	unsigned char addr[ETH_ALEN];
@@ -1083,6 +1083,7 @@ static void
 mlxsw_sp_crif_init(struct mlxsw_sp_crif *crif, struct net_device *dev)
 {
 	crif->key.dev = dev;
+	INIT_LIST_HEAD(&crif->nexthop_list);
 }
 
 static struct mlxsw_sp_crif *
@@ -1103,6 +1104,7 @@ static void mlxsw_sp_crif_free(struct mlxsw_sp_crif *crif)
 	if (WARN_ON(crif->rif))
 		return;
 
+	WARN_ON(!list_empty(&crif->nexthop_list));
 	kfree(crif);
 }
 
@@ -1720,17 +1722,26 @@ static void mlxsw_sp_netdevice_ipip_ol_down_event(struct mlxsw_sp *mlxsw_sp,
 		mlxsw_sp_ipip_entry_ol_down_event(mlxsw_sp, ipip_entry);
 }
 
-static void mlxsw_sp_nexthop_rif_migrate(struct mlxsw_sp *mlxsw_sp,
-					 struct mlxsw_sp_rif *old_rif,
-					 struct mlxsw_sp_rif *new_rif);
+static void mlxsw_sp_nexthop_rif_update(struct mlxsw_sp *mlxsw_sp,
+					struct mlxsw_sp_rif *rif);
+
 static void mlxsw_sp_rif_migrate_destroy(struct mlxsw_sp *mlxsw_sp,
 					 struct mlxsw_sp_rif *old_rif,
 					 struct mlxsw_sp_rif *new_rif,
 					 bool migrate_nhs)
 {
+	struct mlxsw_sp_crif *crif = old_rif->crif;
+	struct mlxsw_sp_crif mock_crif = {};
+
 	if (migrate_nhs)
-		mlxsw_sp_nexthop_rif_migrate(mlxsw_sp, old_rif, new_rif);
+		mlxsw_sp_nexthop_rif_update(mlxsw_sp, new_rif);
 
+	/* Plant a mock CRIF so that destroying the old RIF doesn't unoffload
+	 * our nexthops and IPIP tunnels, and doesn't sever the crif->rif link.
+	 */
+	mlxsw_sp_crif_init(&mock_crif, crif->key.dev);
+	old_rif->crif = &mock_crif;
+	mock_crif.rif = old_rif;
 	mlxsw_sp_rif_destroy(old_rif);
 }
 
@@ -1756,9 +1767,6 @@ mlxsw_sp_ipip_entry_ol_lb_update(struct mlxsw_sp *mlxsw_sp,
 	return 0;
 }
 
-static void mlxsw_sp_nexthop_rif_update(struct mlxsw_sp *mlxsw_sp,
-					struct mlxsw_sp_rif *rif);
-
 /**
  * __mlxsw_sp_ipip_entry_update_tunnel - Update offload related to IPIP entry.
  * @mlxsw_sp: mlxsw_sp.
@@ -2987,7 +2995,7 @@ struct mlxsw_sp_nexthop_key {
 
 struct mlxsw_sp_nexthop {
 	struct list_head neigh_list_node; /* member of neigh entry list */
-	struct list_head rif_list_node;
+	struct list_head crif_list_node;
 	struct list_head router_list_node;
 	struct mlxsw_sp_nexthop_group_info *nhgi; /* pointer back to the group
 						   * this nexthop belongs to
@@ -3000,7 +3008,7 @@ struct mlxsw_sp_nexthop {
 	int nh_weight;
 	int norm_nh_weight;
 	int num_adj_entries;
-	struct mlxsw_sp_rif *rif;
+	struct mlxsw_sp_crif *crif;
 	u8 should_offload:1, /* set indicates this nexthop should be written
 			      * to the adjacency table.
 			      */
@@ -3023,9 +3031,9 @@ struct mlxsw_sp_nexthop {
 static struct net_device *
 mlxsw_sp_nexthop_dev(const struct mlxsw_sp_nexthop *nh)
 {
-	if (nh->rif)
-		return mlxsw_sp_rif_dev(nh->rif);
-	return NULL;
+	if (!nh->crif)
+		return NULL;
+	return nh->crif->key.dev;
 }
 
 enum mlxsw_sp_nexthop_group_type {
@@ -3050,7 +3058,11 @@ struct mlxsw_sp_nexthop_group_info {
 static struct mlxsw_sp_rif *
 mlxsw_sp_nhgi_rif(const struct mlxsw_sp_nexthop_group_info *nhgi)
 {
-	return nhgi->nexthops[0].rif;
+	struct mlxsw_sp_crif *crif = nhgi->nexthops[0].crif;
+
+	if (!crif)
+		return NULL;
+	return crif->rif;
 }
 
 struct mlxsw_sp_nexthop_group_vr_key {
@@ -3174,7 +3186,9 @@ int mlxsw_sp_nexthop_indexes(struct mlxsw_sp_nexthop *nh, u32 *p_adj_index,
 
 struct mlxsw_sp_rif *mlxsw_sp_nexthop_rif(struct mlxsw_sp_nexthop *nh)
 {
-	return nh->rif;
+	if (WARN_ON(!nh->crif))
+		return NULL;
+	return nh->crif->rif;
 }
 
 bool mlxsw_sp_nexthop_group_has_ipip(struct mlxsw_sp_nexthop *nh)
@@ -3559,11 +3573,12 @@ static int __mlxsw_sp_nexthop_eth_update(struct mlxsw_sp *mlxsw_sp,
 					 bool force, char *ratr_pl)
 {
 	struct mlxsw_sp_neigh_entry *neigh_entry = nh->neigh_entry;
+	struct mlxsw_sp_rif *rif = mlxsw_sp_nexthop_rif(nh);
 	enum mlxsw_reg_ratr_op op;
 	u16 rif_index;
 
-	rif_index = nh->rif ? nh->rif->rif_index :
-			      mlxsw_sp->router->lb_crif->rif->rif_index;
+	rif_index = rif ? rif->rif_index :
+			  mlxsw_sp->router->lb_crif->rif->rif_index;
 	op = force ? MLXSW_REG_RATR_OP_WRITE_WRITE_ENTRY :
 		     MLXSW_REG_RATR_OP_WRITE_WRITE_ENTRY_ON_ACTIVITY;
 	mlxsw_reg_ratr_pack(ratr_pl, op, true, MLXSW_REG_RATR_TYPE_ETHERNET,
@@ -4181,23 +4196,23 @@ mlxsw_sp_nexthop_neigh_update(struct mlxsw_sp *mlxsw_sp,
 	}
 }
 
-static void mlxsw_sp_nexthop_rif_init(struct mlxsw_sp_nexthop *nh,
-				      struct mlxsw_sp_rif *rif)
+static void mlxsw_sp_nexthop_crif_init(struct mlxsw_sp_nexthop *nh,
+				       struct mlxsw_sp_crif *crif)
 {
-	if (nh->rif)
+	if (nh->crif)
 		return;
 
-	nh->rif = rif;
-	list_add(&nh->rif_list_node, &rif->nexthop_list);
+	nh->crif = crif;
+	list_add(&nh->crif_list_node, &crif->nexthop_list);
 }
 
-static void mlxsw_sp_nexthop_rif_fini(struct mlxsw_sp_nexthop *nh)
+static void mlxsw_sp_nexthop_crif_fini(struct mlxsw_sp_nexthop *nh)
 {
-	if (!nh->rif)
+	if (!nh->crif)
 		return;
 
-	list_del(&nh->rif_list_node);
-	nh->rif = NULL;
+	list_del(&nh->crif_list_node);
+	nh->crif = NULL;
 }
 
 static int mlxsw_sp_nexthop_neigh_init(struct mlxsw_sp *mlxsw_sp,
@@ -4209,6 +4224,9 @@ static int mlxsw_sp_nexthop_neigh_init(struct mlxsw_sp *mlxsw_sp,
 	u8 nud_state, dead;
 	int err;
 
+	if (WARN_ON(!nh->crif->rif))
+		return 0;
+
 	if (!nh->nhgi->gateway || nh->neigh_entry)
 		return 0;
 	dev = mlxsw_sp_nexthop_dev(nh);
@@ -4299,15 +4317,20 @@ static void mlxsw_sp_nexthop_ipip_init(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_nexthop *nh,
 				       struct mlxsw_sp_ipip_entry *ipip_entry)
 {
+	struct mlxsw_sp_crif *crif;
 	bool removing;
 
 	if (!nh->nhgi->gateway || nh->ipip_entry)
 		return;
 
+	crif = mlxsw_sp_crif_lookup(mlxsw_sp->router, ipip_entry->ol_dev);
+	if (WARN_ON(!crif))
+		return;
+
 	nh->ipip_entry = ipip_entry;
 	removing = !mlxsw_sp_ipip_netdev_ul_up(ipip_entry->ol_dev);
 	__mlxsw_sp_nexthop_neigh_update(nh, removing);
-	mlxsw_sp_nexthop_rif_init(nh, &ipip_entry->ol_lb->common);
+	mlxsw_sp_nexthop_crif_init(nh, crif);
 }
 
 static void mlxsw_sp_nexthop_ipip_fini(struct mlxsw_sp *mlxsw_sp,
@@ -4339,7 +4362,7 @@ static int mlxsw_sp_nexthop_type_init(struct mlxsw_sp *mlxsw_sp,
 {
 	const struct mlxsw_sp_ipip_ops *ipip_ops;
 	struct mlxsw_sp_ipip_entry *ipip_entry;
-	struct mlxsw_sp_rif *rif;
+	struct mlxsw_sp_crif *crif;
 	int err;
 
 	ipip_entry = mlxsw_sp_ipip_entry_find_by_ol_dev(mlxsw_sp, dev);
@@ -4353,19 +4376,23 @@ static int mlxsw_sp_nexthop_type_init(struct mlxsw_sp *mlxsw_sp,
 	}
 
 	nh->type = MLXSW_SP_NEXTHOP_TYPE_ETH;
-	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);
-	if (!rif)
+	crif = mlxsw_sp_crif_lookup(mlxsw_sp->router, dev);
+	if (!crif)
+		return 0;
+
+	mlxsw_sp_nexthop_crif_init(nh, crif);
+
+	if (!crif->rif)
 		return 0;
 
-	mlxsw_sp_nexthop_rif_init(nh, rif);
 	err = mlxsw_sp_nexthop_neigh_init(mlxsw_sp, nh);
 	if (err)
 		goto err_neigh_init;
 
 	return 0;
 
 err_neigh_init:
-	mlxsw_sp_nexthop_rif_fini(nh);
+	mlxsw_sp_nexthop_crif_fini(nh);
 	return err;
 }
 
@@ -4386,7 +4413,7 @@ static void mlxsw_sp_nexthop_type_fini(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_nexthop *nh)
 {
 	mlxsw_sp_nexthop_type_rif_gone(mlxsw_sp, nh);
-	mlxsw_sp_nexthop_rif_fini(nh);
+	mlxsw_sp_nexthop_crif_fini(nh);
 }
 
 static int mlxsw_sp_nexthop4_init(struct mlxsw_sp *mlxsw_sp,
@@ -4479,7 +4506,7 @@ static void mlxsw_sp_nexthop_rif_update(struct mlxsw_sp *mlxsw_sp,
 	struct mlxsw_sp_nexthop *nh;
 	bool removing;
 
-	list_for_each_entry(nh, &rif->nexthop_list, rif_list_node) {
+	list_for_each_entry(nh, &rif->crif->nexthop_list, crif_list_node) {
 		switch (nh->type) {
 		case MLXSW_SP_NEXTHOP_TYPE_ETH:
 			removing = false;
@@ -4497,25 +4524,14 @@ static void mlxsw_sp_nexthop_rif_update(struct mlxsw_sp *mlxsw_sp,
 	}
 }
 
-static void mlxsw_sp_nexthop_rif_migrate(struct mlxsw_sp *mlxsw_sp,
-					 struct mlxsw_sp_rif *old_rif,
-					 struct mlxsw_sp_rif *new_rif)
-{
-	struct mlxsw_sp_nexthop *nh;
-
-	list_splice_init(&old_rif->nexthop_list, &new_rif->nexthop_list);
-	list_for_each_entry(nh, &new_rif->nexthop_list, rif_list_node)
-		nh->rif = new_rif;
-	mlxsw_sp_nexthop_rif_update(mlxsw_sp, new_rif);
-}
-
 static void mlxsw_sp_nexthop_rif_gone_sync(struct mlxsw_sp *mlxsw_sp,
 					   struct mlxsw_sp_rif *rif)
 {
 	struct mlxsw_sp_nexthop *nh, *tmp;
 
-	list_for_each_entry_safe(nh, tmp, &rif->nexthop_list, rif_list_node) {
-		mlxsw_sp_nexthop_type_fini(mlxsw_sp, nh);
+	list_for_each_entry_safe(nh, tmp, &rif->crif->nexthop_list,
+				 crif_list_node) {
+		mlxsw_sp_nexthop_type_rif_gone(mlxsw_sp, nh);
 		mlxsw_sp_nexthop_group_refresh(mlxsw_sp, nh->nhgi->nh_grp);
 	}
 }
@@ -4857,13 +4873,13 @@ static void mlxsw_sp_nexthop_obj_blackhole_init(struct mlxsw_sp *mlxsw_sp,
 	 * via an egress RIF, they still need to be programmed using a
 	 * valid RIF, so use the loopback RIF created during init.
 	 */
-	nh->rif = mlxsw_sp->router->lb_crif->rif;
+	nh->crif = mlxsw_sp->router->lb_crif;
 }
 
 static void mlxsw_sp_nexthop_obj_blackhole_fini(struct mlxsw_sp *mlxsw_sp,
 						struct mlxsw_sp_nexthop *nh)
 {
-	nh->rif = NULL;
+	nh->crif = NULL;
 	nh->should_offload = 0;
 }
 
@@ -7871,6 +7887,9 @@ static int mlxsw_sp_router_rif_disable(struct mlxsw_sp *mlxsw_sp, u16 rif)
 static void mlxsw_sp_router_rif_gone_sync(struct mlxsw_sp *mlxsw_sp,
 					  struct mlxsw_sp_rif *rif)
 {
+	/* Signal to nexthop cleanup that the RIF is going away. */
+	rif->crif->rif = NULL;
+
 	mlxsw_sp_router_rif_disable(mlxsw_sp, rif->rif_index);
 	mlxsw_sp_nexthop_rif_gone_sync(mlxsw_sp, rif);
 	mlxsw_sp_neigh_rif_gone_sync(mlxsw_sp, rif);
@@ -7989,7 +8008,6 @@ static struct mlxsw_sp_rif *mlxsw_sp_rif_alloc(size_t rif_size, u16 rif_index,
 	if (!rif)
 		return NULL;
 
-	INIT_LIST_HEAD(&rif->nexthop_list);
 	INIT_LIST_HEAD(&rif->neigh_list);
 	if (l3_dev) {
 		ether_addr_copy(rif->addr, l3_dev->dev_addr);
@@ -8008,7 +8026,6 @@ static struct mlxsw_sp_rif *mlxsw_sp_rif_alloc(size_t rif_size, u16 rif_index,
 static void mlxsw_sp_rif_free(struct mlxsw_sp_rif *rif)
 {
 	WARN_ON(!list_empty(&rif->neigh_list));
-	WARN_ON(!list_empty(&rif->nexthop_list));
 
 	if (rif->crif)
 		rif->crif->rif = NULL;
@@ -9290,7 +9307,13 @@ mlxsw_sp_crif_register(struct mlxsw_sp_router *router, struct net_device *dev)
 static void mlxsw_sp_crif_unregister(struct mlxsw_sp_router *router,
 				     struct mlxsw_sp_crif *crif)
 {
+	struct mlxsw_sp_nexthop *nh, *tmp;
+
 	mlxsw_sp_crif_remove(router, crif);
+
+	list_for_each_entry_safe(nh, tmp, &crif->nexthop_list, crif_list_node)
+		mlxsw_sp_nexthop_type_fini(router->mlxsw_sp, nh);
+
 	if (crif->rif)
 		crif->can_destroy = true;
 	else