Merge branch 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core/locking changes for v3.4 from Ingo Molnar

* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Simplify return logic
  futex: Cover all PI opcodes with cmpxchg enabled check

kernel/futex.c

@@ -2628,7 +2628,7 @@ void exit_robust_list(struct task_struct *curr)
 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 		u32 __user *uaddr2, u32 val2, u32 val3)
 {
-	int ret = -ENOSYS, cmd = op & FUTEX_CMD_MASK;
+	int cmd = op & FUTEX_CMD_MASK;
 	unsigned int flags = 0;
 
 	if (!(op & FUTEX_PRIVATE_FLAG))
@@ -2640,50 +2640,45 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 			return -ENOSYS;
 	}
 
+	switch (cmd) {
+	case FUTEX_LOCK_PI:
+	case FUTEX_UNLOCK_PI:
+	case FUTEX_TRYLOCK_PI:
+	case FUTEX_WAIT_REQUEUE_PI:
+	case FUTEX_CMP_REQUEUE_PI:
+		if (!futex_cmpxchg_enabled)
+			return -ENOSYS;
+	}
+
 	switch (cmd) {
 	case FUTEX_WAIT:
 		val3 = FUTEX_BITSET_MATCH_ANY;
 	case FUTEX_WAIT_BITSET:
-		ret = futex_wait(uaddr, flags, val, timeout, val3);
-		break;
+		return futex_wait(uaddr, flags, val, timeout, val3);
 	case FUTEX_WAKE:
 		val3 = FUTEX_BITSET_MATCH_ANY;
 	case FUTEX_WAKE_BITSET:
-		ret = futex_wake(uaddr, flags, val, val3);
-		break;
+		return futex_wake(uaddr, flags, val, val3);
 	case FUTEX_REQUEUE:
-		ret = futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
-		break;
+		return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
 	case FUTEX_CMP_REQUEUE:
-		ret = futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
-		break;
+		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
 	case FUTEX_WAKE_OP:
-		ret = futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
-		break;
+		return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
 	case FUTEX_LOCK_PI:
-		if (futex_cmpxchg_enabled)
-			ret = futex_lock_pi(uaddr, flags, val, timeout, 0);
-		break;
+		return futex_lock_pi(uaddr, flags, val, timeout, 0);
 	case FUTEX_UNLOCK_PI:
-		if (futex_cmpxchg_enabled)
-			ret = futex_unlock_pi(uaddr, flags);
-		break;
+		return futex_unlock_pi(uaddr, flags);
 	case FUTEX_TRYLOCK_PI:
-		if (futex_cmpxchg_enabled)
-			ret = futex_lock_pi(uaddr, flags, 0, timeout, 1);
-		break;
+		return futex_lock_pi(uaddr, flags, 0, timeout, 1);
 	case FUTEX_WAIT_REQUEUE_PI:
 		val3 = FUTEX_BITSET_MATCH_ANY;
-		ret = futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
-					    uaddr2);
-		break;
+		return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
+					     uaddr2);
 	case FUTEX_CMP_REQUEUE_PI:
-		ret = futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
-		break;
-	default:
-		ret = -ENOSYS;
+		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
 	}
-	return ret;
+	return -ENOSYS;
 }