[NETNS][IPV6]: Make ipv6_sysctl_register to return a value.

This patch makes the function ipv6_sysctl_register to return a
value. The af_inet6 init function is now able to handle an error and
catch it from the initialization of the sysctl.
Signed-off-by: NDaniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -622,7 +622,7 @@ static inline int snmp6_unregister_dev(struct inet6_dev *idev)
 extern ctl_table ipv6_route_table[];
 extern ctl_table ipv6_icmp_table[];
 
-extern void ipv6_sysctl_register(void);
+extern int ipv6_sysctl_register(void);
 extern void ipv6_sysctl_unregister(void);
 #endif
 

net/ipv6/af_inet6.c

@@ -783,7 +783,9 @@ static int __init inet6_init(void)
 	 */
 
 #ifdef CONFIG_SYSCTL
-	ipv6_sysctl_register();
+	err = ipv6_sysctl_register();
+	if (err)
+		goto sysctl_fail;
 #endif
 	err = icmpv6_init(&inet6_family_ops);
 	if (err)
@@ -897,6 +899,7 @@ static int __init inet6_init(void)
 icmp_fail:
 #ifdef CONFIG_SYSCTL
 	ipv6_sysctl_unregister();
+sysctl_fail:
 #endif
 	cleanup_ipv6_mibs();
 out_unregister_sock:

net/ipv6/sysctl_net_ipv6.c

@@ -91,10 +91,15 @@ EXPORT_SYMBOL_GPL(net_ipv6_ctl_path);
 
 static struct ctl_table_header *ipv6_sysctl_header;
 
-void ipv6_sysctl_register(void)
+int ipv6_sysctl_register(void)
 {
 	ipv6_sysctl_header = register_sysctl_paths(net_ipv6_ctl_path,
-			ipv6_table);
+						   ipv6_table);
+	if (!ipv6_sysctl_header)
+		return -ENOMEM;
+
+	return 0;
+
 }
 
 void ipv6_sysctl_unregister(void)