Re: [PATCH v3 net-next 03/13] ipv4: Create init helper for fib_nh

[Ido Schimmel <idosch@mellanox.com>]

On Wed, Mar 27, 2019 at 08:53:48PM -0700, David Ahern wrote:
> From: David Ahern <dsahern@gmail.com>
> 
> Consolidate the fib_nh initialization which is duplicated between
> fib_create_info for single path and fib_get_nhs for multipath.
> Export the helper to allow for use with nexthop objects in the
> future.
> 
> Signed-off-by: David Ahern <dsahern@gmail.com>

Reviewed-by: Ido Schimmel <idosch@mellanox.com>

One comment below.

> +int fib_nh_init(struct net *net, struct fib_nh *nh,
> +		struct fib_config *cfg, int nh_weight,
> +		struct netlink_ext_ack *extack)
> +{
> +	int err = -ENOMEM;
> +
> +	nh->nh_pcpu_rth_output = alloc_percpu(struct rtable __rcu *);
> +	if (!nh->nh_pcpu_rth_output)
> +		goto err_out;
> +
> +	if (cfg->fc_encap) {
> +		struct lwtunnel_state *lwtstate;
> +
> +		err = -EINVAL;
> +		if (cfg->fc_encap_type == LWTUNNEL_ENCAP_NONE) {
> +			NL_SET_ERR_MSG(extack, "LWT encap type not specified");
> +			goto lwt_failure;
> +		}
> +		err = lwtunnel_build_state(cfg->fc_encap_type,
> +					   cfg->fc_encap, AF_INET, cfg,
> +					   &lwtstate, extack);
> +		if (err)
> +			goto lwt_failure;
> +
> +		nh->nh_lwtstate = lwtstate_get(lwtstate);
> +	}
> +
> +	nh->nh_oif = cfg->fc_oif;
> +	nh->nh_gw = cfg->fc_gw;
> +	nh->nh_flags = cfg->fc_flags;
> +
> +#ifdef CONFIG_IP_ROUTE_CLASSID
> +	nh->nh_tclassid = cfg->fc_flow;
> +	if (nh->nh_tclassid)
> +		net->ipv4.fib_num_tclassid_users++;
> +#endif
> +#ifdef CONFIG_IP_ROUTE_MULTIPATH
> +	nh->nh_weight = nh_weight;

After this series 'nhc_weight' is always defined in the nexthop struct
because it is shared with IPv6 which does not have a corresponding
Kconfig. This ifdef can be removed from here and probably from a few
other places as well.

> +#endif
> +	return 0;
> +
> +lwt_failure:
> +	rt_fibinfo_free_cpus(nh->nh_pcpu_rth_output);
> +	nh->nh_pcpu_rth_output = NULL;
> +err_out:
> +	return err;
> +}