ipv4: Create cleanup helper for fib_nh

Move the fib_nh cleanup code from free_fib_info_rcu into a new helper,
fib_nh_release. Move classid accounting into fib_nh_release which is
called per fib_nh to make accounting symmetrical with fib_nh_init.
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>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ip_fib.h

@@ -419,6 +419,7 @@ void fib_select_path(struct net *net, struct fib_result *res,
 int fib_nh_init(struct net *net, struct fib_nh *fib_nh,
 		struct fib_config *cfg, int nh_weight,
 		struct netlink_ext_ack *extack);
+void fib_nh_release(struct net *net, struct fib_nh *fib_nh);
 
 /* Exported by fib_trie.c */
 void fib_trie_init(void);

net/ipv4/fib_semantics.c

@@ -204,18 +204,28 @@ static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
 	free_percpu(rtp);
 }
 
+void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
+{
+#ifdef CONFIG_IP_ROUTE_CLASSID
+	if (fib_nh->nh_tclassid)
+		net->ipv4.fib_num_tclassid_users--;
+#endif
+	if (fib_nh->nh_dev)
+		dev_put(fib_nh->nh_dev);
+
+	lwtstate_put(fib_nh->nh_lwtstate);
+	free_nh_exceptions(fib_nh);
+	rt_fibinfo_free_cpus(fib_nh->nh_pcpu_rth_output);
+	rt_fibinfo_free(&fib_nh->nh_rth_input);
+}
+
 /* Release a nexthop info record */
 static void free_fib_info_rcu(struct rcu_head *head)
 {
 	struct fib_info *fi = container_of(head, struct fib_info, rcu);
 
 	change_nexthops(fi) {
-		if (nexthop_nh->nh_dev)
-			dev_put(nexthop_nh->nh_dev);
-		lwtstate_put(nexthop_nh->nh_lwtstate);
-		free_nh_exceptions(nexthop_nh);
-		rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output);
-		rt_fibinfo_free(&nexthop_nh->nh_rth_input);
+		fib_nh_release(fi->fib_net, nexthop_nh);
 	} endfor_nexthops(fi);
 
 	ip_fib_metrics_put(fi->fib_metrics);
@@ -230,12 +240,7 @@ void free_fib_info(struct fib_info *fi)
 		return;
 	}
 	fib_info_cnt--;
-#ifdef CONFIG_IP_ROUTE_CLASSID
-	change_nexthops(fi) {
-		if (nexthop_nh->nh_tclassid)
-			fi->fib_net->ipv4.fib_num_tclassid_users--;
-	} endfor_nexthops(fi);
-#endif
+
 	call_rcu(&fi->rcu, free_fib_info_rcu);
 }
 EXPORT_SYMBOL_GPL(free_fib_info);