make sock_alloc_file() do sock_release() on failures

This changes calling conventions (and simplifies the hell out
the callers).  New rules: once struct socket had been passed
to sock_alloc_file(), it's been consumed either by struct file
or by sock_release() done by sock_alloc_file().  Either way
the caller should not do sock_release() after that point.

Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index c5fa634..d4e98f2 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1629,7 +1629,6 @@ static struct file *kcm_clone(struct socket *osock)
 {
 	struct socket *newsock;
 	struct sock *newsk;
-	struct file *file;
 
 	newsock = sock_alloc();
 	if (!newsock)
@@ -1649,11 +1648,7 @@ static struct file *kcm_clone(struct socket *osock)
 	sock_init_data(newsock, newsk);
 	init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);
 
-	file = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
-	if (IS_ERR(file))
-		sock_release(newsock);
-
-	return file;
+	return sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
 }
 
 static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)