[IPV6]: Make fib6_rules_init to return an error code.

When the fib_rules initialization finished, no return code is provided
so there is no way to know, for the caller, if the initialization has
been successful or has failed. This patch fix that.
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Benjamin Thery <benjamin.thery@bull.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/fib_rules.h

@@ -103,6 +103,7 @@ static inline u32 frh_get_table(struct fib_rule_hdr *frh, struct nlattr **nla)
 
 extern int			fib_rules_register(struct fib_rules_ops *);
 extern int			fib_rules_unregister(struct fib_rules_ops *);
+extern void                     fib_rules_cleanup_ops(struct fib_rules_ops *);
 
 extern int			fib_rules_lookup(struct fib_rules_ops *,
 						 struct flowi *, int flags,

include/net/ip6_fib.h

@@ -226,7 +226,7 @@ extern void			fib6_gc_cleanup(void);
 
 extern int			fib6_init(void);
 
-extern void			fib6_rules_init(void);
+extern int			fib6_rules_init(void);
 extern void			fib6_rules_cleanup(void);
 
 #endif

net/core/fib_rules.c

@@ -102,7 +102,7 @@ int fib_rules_register(struct fib_rules_ops *ops)
 
 EXPORT_SYMBOL_GPL(fib_rules_register);
 
-static void cleanup_ops(struct fib_rules_ops *ops)
+void fib_rules_cleanup_ops(struct fib_rules_ops *ops)
 {
 	struct fib_rule *rule, *tmp;
 
@@ -111,6 +111,7 @@ static void cleanup_ops(struct fib_rules_ops *ops)
 		fib_rule_put(rule);
 	}
 }
+EXPORT_SYMBOL_GPL(fib_rules_cleanup_ops);
 
 int fib_rules_unregister(struct fib_rules_ops *ops)
 {
@@ -121,7 +122,7 @@ int fib_rules_unregister(struct fib_rules_ops *ops)
 	list_for_each_entry(o, &rules_ops, list) {
 		if (o == ops) {
 			list_del_rcu(&o->list);
-			cleanup_ops(ops);
+			fib_rules_cleanup_ops(ops);
 			goto out;
 		}
 	}

net/ipv6/fib6_rules.c

@@ -265,10 +265,23 @@ static int __init fib6_default_rules_init(void)
 	return 0;
 }
 
-void __init fib6_rules_init(void)
+int __init fib6_rules_init(void)
 {
-	BUG_ON(fib6_default_rules_init());
-	fib_rules_register(&fib6_rules_ops);
+	int ret;
+
+	ret = fib6_default_rules_init();
+	if (ret)
+		goto out;
+
+	ret = fib_rules_register(&fib6_rules_ops);
+	if (ret)
+		goto out_default_rules_init;
+out:
+	return ret;
+
+out_default_rules_init:
+	fib_rules_cleanup_ops(&fib6_rules_ops);
+	goto out;
 }
 
 void fib6_rules_cleanup(void)