futex: fix futex_wait_setup key handling

If the get_futex_key() call were to fail, the existing code would
try and put_futex_key() prior to returning.  This patch makes sure
we only put_futex_key() if get_futex_key() succeeded.

Reported-by: Clark Williams <williams@redhat.com>
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
LKML-Reference: <20090410165005.14342.16973.stgit@Aeon>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/futex.c

@@ -1668,7 +1668,7 @@ retry:
 	q->key = FUTEX_KEY_INIT;
 	ret = get_futex_key(uaddr, fshared, &q->key);
 	if (unlikely(ret != 0))
-		goto out;
+		return ret;
 
 retry_private:
 	*hb = queue_lock(q);