diff --git a/[refs] b/[refs]
index f1ca2ee390db..0141bb3b7041 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 385ab5bcd4be586dffdba550b310308d89eade71
+refs/heads/master: 9cac00b8f0079d5d3d54ec4dae453d58dec30e7c
diff --git a/trunk/drivers/firewire/core-cdev.c b/trunk/drivers/firewire/core-cdev.c
index 5eba9e0f876c..0d3df0927efc 100644
--- a/trunk/drivers/firewire/core-cdev.c
+++ b/trunk/drivers/firewire/core-cdev.c
@@ -1356,24 +1356,24 @@ static int dispatch_ioctl(struct client *client,
 		return -ENODEV;
 
 	if (_IOC_TYPE(cmd) != '#' ||
-	    _IOC_NR(cmd) >= ARRAY_SIZE(ioctl_handlers))
+	    _IOC_NR(cmd) >= ARRAY_SIZE(ioctl_handlers) ||
+	    _IOC_SIZE(cmd) > sizeof(buffer))
 		return -EINVAL;
 
-	if (_IOC_DIR(cmd) & _IOC_WRITE) {
-		if (_IOC_SIZE(cmd) > sizeof(buffer) ||
-		    copy_from_user(&buffer, arg, _IOC_SIZE(cmd)))
+	if (_IOC_DIR(cmd) == _IOC_READ)
+		memset(&buffer, 0, _IOC_SIZE(cmd));
+
+	if (_IOC_DIR(cmd) & _IOC_WRITE)
+		if (copy_from_user(&buffer, arg, _IOC_SIZE(cmd)))
 			return -EFAULT;
-	}
 
 	ret = ioctl_handlers[_IOC_NR(cmd)](client, &buffer);
 	if (ret < 0)
 		return ret;
 
-	if (_IOC_DIR(cmd) & _IOC_READ) {
-		if (_IOC_SIZE(cmd) > sizeof(buffer) ||
-		    copy_to_user(arg, &buffer, _IOC_SIZE(cmd)))
+	if (_IOC_DIR(cmd) & _IOC_READ)
+		if (copy_to_user(arg, &buffer, _IOC_SIZE(cmd)))
 			return -EFAULT;
-	}
 
 	return ret;
 }