mlxsw: spectrum_router: Handle encap to demoted tunnels

Some tunnels that are offloadable on their own can nonetheless be
demoted to slow path if their local address is in conflict with that of
another tunnel. When a route is formed for such a tunnel,
mlxsw_sp_nexthop_ipip_init() fails to find the corresponding IPIP entry,
and that triggers a FIB abort.

Resolve the problem by not assuming that a tunnel for which
mlxsw_sp_ipip_ops.can_offload() holds also automatically has an IPIP
entry.

Fixes: af641713 ("mlxsw: spectrum_router: Onload conflicting tunnels")
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_router.c

@@ -3361,22 +3361,19 @@ static bool mlxsw_sp_ipip_netdev_ul_up(struct net_device *ol_dev)
 	return ul_dev ? (ul_dev->flags & IFF_UP) : true;
 }
 
-static int mlxsw_sp_nexthop_ipip_init(struct mlxsw_sp *mlxsw_sp,
+static void mlxsw_sp_nexthop_ipip_init(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_nexthop *nh,
-				      struct net_device *ol_dev)
+				       struct mlxsw_sp_ipip_entry *ipip_entry)
 {
 	bool removing;
 
 	if (!nh->nh_grp->gateway || nh->ipip_entry)
-		return 0;
-
-	nh->ipip_entry = mlxsw_sp_ipip_entry_find_by_ol_dev(mlxsw_sp, ol_dev);
-	if (!nh->ipip_entry)
-		return -ENOENT;
+		return;
 
-	removing = !mlxsw_sp_ipip_netdev_ul_up(ol_dev);
+	nh->ipip_entry = ipip_entry;
+	removing = !mlxsw_sp_ipip_netdev_ul_up(ipip_entry->ol_dev);
 	__mlxsw_sp_nexthop_neigh_update(nh, removing);
-	return 0;
+	mlxsw_sp_nexthop_rif_init(nh, &ipip_entry->ol_lb->common);
 }
 
 static void mlxsw_sp_nexthop_ipip_fini(struct mlxsw_sp *mlxsw_sp,
@@ -3421,22 +3418,22 @@ static int mlxsw_sp_nexthop4_type_init(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_nexthop *nh,
 				       struct fib_nh *fib_nh)
 {
-	struct mlxsw_sp_router *router = mlxsw_sp->router;
+	const struct mlxsw_sp_ipip_ops *ipip_ops;
 	struct net_device *dev = fib_nh->nh_dev;
-	enum mlxsw_sp_ipip_type ipipt;
+	struct mlxsw_sp_ipip_entry *ipip_entry;
 	struct mlxsw_sp_rif *rif;
 	int err;
 
-	if (mlxsw_sp_nexthop4_ipip_type(mlxsw_sp, fib_nh, &ipipt) &&
-	    router->ipip_ops_arr[ipipt]->can_offload(mlxsw_sp, dev,
+	ipip_entry = mlxsw_sp_ipip_entry_find_by_ol_dev(mlxsw_sp, dev);
+	if (ipip_entry) {
+		ipip_ops = mlxsw_sp->router->ipip_ops_arr[ipip_entry->ipipt];
+		if (ipip_ops->can_offload(mlxsw_sp, dev,
 					  MLXSW_SP_L3_PROTO_IPV4)) {
 			nh->type = MLXSW_SP_NEXTHOP_TYPE_IPIP;
-		err = mlxsw_sp_nexthop_ipip_init(mlxsw_sp, nh, dev);
-		if (err)
-			return err;
-		mlxsw_sp_nexthop_rif_init(nh, &nh->ipip_entry->ol_lb->common);
+			mlxsw_sp_nexthop_ipip_init(mlxsw_sp, nh, ipip_entry);
 			return 0;
 		}
+	}
 
 	nh->type = MLXSW_SP_NEXTHOP_TYPE_ETH;
 	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);
@@ -4712,22 +4709,22 @@ static int mlxsw_sp_nexthop6_type_init(struct mlxsw_sp *mlxsw_sp,
 				       struct mlxsw_sp_nexthop *nh,
 				       const struct rt6_info *rt)
 {
-	struct mlxsw_sp_router *router = mlxsw_sp->router;
+	const struct mlxsw_sp_ipip_ops *ipip_ops;
+	struct mlxsw_sp_ipip_entry *ipip_entry;
 	struct net_device *dev = rt->dst.dev;
-	enum mlxsw_sp_ipip_type ipipt;
 	struct mlxsw_sp_rif *rif;
 	int err;
 
-	if (mlxsw_sp_nexthop6_ipip_type(mlxsw_sp, rt, &ipipt) &&
-	    router->ipip_ops_arr[ipipt]->can_offload(mlxsw_sp, dev,
+	ipip_entry = mlxsw_sp_ipip_entry_find_by_ol_dev(mlxsw_sp, dev);
+	if (ipip_entry) {
+		ipip_ops = mlxsw_sp->router->ipip_ops_arr[ipip_entry->ipipt];
+		if (ipip_ops->can_offload(mlxsw_sp, dev,
 					  MLXSW_SP_L3_PROTO_IPV6)) {
 			nh->type = MLXSW_SP_NEXTHOP_TYPE_IPIP;
-		err = mlxsw_sp_nexthop_ipip_init(mlxsw_sp, nh, dev);
-		if (err)
-			return err;
-		mlxsw_sp_nexthop_rif_init(nh, &nh->ipip_entry->ol_lb->common);
+			mlxsw_sp_nexthop_ipip_init(mlxsw_sp, nh, ipip_entry);
 			return 0;
 		}
+	}
 
 	nh->type = MLXSW_SP_NEXTHOP_TYPE_ETH;
 	rif = mlxsw_sp_rif_find_by_dev(mlxsw_sp, dev);