mlxsw: spectrum_router: Maintain CRIF for fallback loopback RIF

CRIFs are generally not maintained for loopback RIFs. However, the RIF for
the default VRF is used for offloading of blackhole nexthops. Nexthops
expect to have a valid CRIF. Therefore in this patch, add code to maintain
CRIF for the loopback RIF as well.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Danielle Ratson <danieller@nvidia.com>
Link: https://lore.kernel.org/r/7f2b2fcc98770167ed1254a904c3f7f585ba43f0.1687438411.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

@@ -10731,27 +10731,37 @@ static void __mlxsw_sp_router_fini(struct mlxsw_sp *mlxsw_sp)
 static int mlxsw_sp_lb_rif_init(struct mlxsw_sp *mlxsw_sp,
 				struct netlink_ext_ack *extack)
 {
+	struct mlxsw_sp_router *router = mlxsw_sp->router;
 	struct mlxsw_sp_rif *lb_rif;
 	int err;
 
+	router->lb_crif = mlxsw_sp_crif_alloc(NULL);
+	if (IS_ERR(router->lb_crif))
+		return PTR_ERR(router->lb_crif);
+
 	/* Create a generic loopback RIF associated with the main table
 	 * (default VRF). Any table can be used, but the main table exists
 	 * anyway, so we do not waste resources.
 	 */
 	lb_rif = mlxsw_sp_ul_rif_get(mlxsw_sp, RT_TABLE_MAIN, extack);
 	if (IS_ERR(lb_rif)) {
 		err = PTR_ERR(lb_rif);
-		return err;
+		goto err_ul_rif_get;
 	}
 
 	mlxsw_sp->router->lb_rif_index = lb_rif->rif_index;
 
 	return 0;
+
+err_ul_rif_get:
+	mlxsw_sp_crif_free(router->lb_crif);
+	return err;
 }
 
 static void mlxsw_sp_lb_rif_fini(struct mlxsw_sp *mlxsw_sp)
 {
 	mlxsw_sp_router_ul_rif_put(mlxsw_sp, mlxsw_sp->router->lb_rif_index);
+	mlxsw_sp_crif_free(mlxsw_sp->router->lb_crif);
 }
 
 static int mlxsw_sp1_router_init(struct mlxsw_sp *mlxsw_sp)

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

@@ -61,6 +61,7 @@ struct mlxsw_sp_router {
 	struct mutex lock; /* Protects shared router resources */
 	struct mlxsw_sp_fib_entry_op_ctx *ll_op_ctx;
 	u16 lb_rif_index;
+	struct mlxsw_sp_crif *lb_crif;
 	const struct mlxsw_sp_adj_grp_size_range *adj_grp_size_ranges;
 	size_t adj_grp_size_ranges_count;
 	struct delayed_work nh_grp_activity_dw;