[IPV6]: make flowlabel to return an error

This patch makes the flowlab subsystem to return an error code and makes
some cleanup with procfs ifdefs.
The af_inet6 will use the flowlabel init return code to check the initialization
was correct.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/ipv6.h

@@ -219,7 +219,7 @@ extern struct ipv6_txoptions	*fl6_merge_options(struct ipv6_txoptions * opt_spac
 						   struct ipv6_txoptions * fopt);
 extern void			fl6_free_socklist(struct sock *sk);
 extern int			ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen);
-extern void			ip6_flowlabel_init(void);
+extern int			ip6_flowlabel_init(void);
 extern void			ip6_flowlabel_cleanup(void);
 
 static inline void fl6_sock_release(struct ip6_flowlabel *fl)

net/ipv6/af_inet6.c

@@ -851,7 +851,9 @@ static int __init inet6_init(void)
 	err = ip6_route_init();
 	if (err)
 		goto ip6_route_fail;
-	ip6_flowlabel_init();
+	err = ip6_flowlabel_init();
+	if (err)
+		goto ip6_flowlabel_fail;
 	err = addrconf_init();
 	if (err)
 		goto addrconf_fail;
@@ -874,6 +876,7 @@ static int __init inet6_init(void)
 
 addrconf_fail:
 	ip6_flowlabel_cleanup();
+ip6_flowlabel_fail:
 	ip6_route_cleanup();
 ip6_route_fail:
 #ifdef CONFIG_PROC_FS

net/ipv6/ip6_flowlabel.c

@@ -692,20 +692,36 @@ static const struct file_operations ip6fl_seq_fops = {
 	.llseek		=	seq_lseek,
 	.release	=	seq_release_private,
 };
-#endif
 
+static int ip6_flowlabel_proc_init(struct net *net)
+{
+	if (!proc_net_fops_create(net, "ip6_flowlabel", S_IRUGO, &ip6fl_seq_fops))
+		return -ENOMEM;
+	return 0;
+}
 
-void ip6_flowlabel_init(void)
+static void ip6_flowlabel_proc_fini(struct net *net)
 {
-#ifdef CONFIG_PROC_FS
-	proc_net_fops_create(&init_net, "ip6_flowlabel", S_IRUGO, &ip6fl_seq_fops);
+	proc_net_remove(net, "ip6_flowlabel");
+}
+#else
+static inline int ip6_flowlabel_proc_init(struct net *net)
+{
+	return 0;
+}
+static inline void ip6_flowlabel_proc_fini(struct net *net)
+{
+	return ;
+}
 #endif
+
+int ip6_flowlabel_init(void)
+{
+	return ip6_flowlabel_proc_init(&init_net);
 }
 
 void ip6_flowlabel_cleanup(void)
 {
 	del_timer(&ip6_fl_gc_timer);
-#ifdef CONFIG_PROC_FS
-	proc_net_remove(&init_net, "ip6_flowlabel");
-#endif
+	ip6_flowlabel_proc_fini(&init_net);
 }