x25: Fix broken locking in ioctl error paths.

BugLink: http://bugs.launchpad.net/bugs/1214984

[ Upstream commit 4ccb93c ]

Two of the x25 ioctl cases have error paths that break out of the function without
unlocking the socket, leading to this warning:

================================================
[ BUG: lock held when returning to user space! ]
3.10.0-rc7+ torvalds#36 Not tainted
------------------------------------------------
trinity-child2/31407 is leaving the kernel with locks still held!
1 lock held by trinity-child2/31407:
 #0:  (sk_lock-AF_X25){+.+.+.}, at: [<ffffffffa024b6da>] x25_ioctl+0x8a/0x740 [x25]

Signed-off-by: Dave Jones <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Ben Hutchings <[email protected]>
Signed-off-by: Brad Figg <[email protected]>

Author: Dave Jones

Diff for: net/x25/af_x25.c

@@ -1586,26 +1586,27 @@ static int x25_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
 	case SIOCX25CALLACCPTAPPRV: {
 		rc = -EINVAL;
 		lock_sock(sk);
-		if (sk->sk_state != TCP_CLOSE)
-			break;
-		clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
+		if (sk->sk_state == TCP_CLOSE) {
+			clear_bit(X25_ACCPT_APPRV_FLAG, &x25->flags);
+			rc = 0;
+		}
 		release_sock(sk);
-		rc = 0;
 		break;
 	}
 
 	case SIOCX25SENDCALLACCPT:  {
 		rc = -EINVAL;
 		lock_sock(sk);
 		if (sk->sk_state != TCP_ESTABLISHED)
-			break;
+			goto out_sendcallaccpt_release;
 		/* must call accptapprv above */
 		if (test_bit(X25_ACCPT_APPRV_FLAG, &x25->flags))
-			break;
+			goto out_sendcallaccpt_release;
 		x25_write_internal(sk, X25_CALL_ACCEPTED);
 		x25->state = X25_STATE_3;
-		release_sock(sk);
 		rc = 0;
+out_sendcallaccpt_release:
+		release_sock(sk);
 		break;
 	}