userns: Print out socket uids in a user namespace aware fashion.

Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: James Morris <jmorris@namei.org>
Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

net/appletalk/atalk_proc.c

@@ -183,7 +183,8 @@ static int atalk_seq_socket_show(struct seq_file *seq, void *v)
 		   ntohs(at->dest_net), at->dest_node, at->dest_port,
 		   sk_wmem_alloc_get(s),
 		   sk_rmem_alloc_get(s),
-		   s->sk_state, SOCK_INODE(s->sk_socket)->i_uid);
+		   s->sk_state,
+		   from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)));
 out:
 	return 0;
 }