IPoIB: Fix world-writable child interface control sysfs attributes

Sumeet Lahorani <sumeet.lahorani@oracle.com> reported that the IPoIB
child entries are world-writable; however we don't want ordinary users
to be able to create and destroy child interfaces, so fix them to be
writable only by root.

Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/ulp/ipoib/ipoib_main.c

@@ -1163,7 +1163,7 @@ static ssize_t create_child(struct device *dev,
 
 	return ret ? ret : count;
 }
-static DEVICE_ATTR(create_child, S_IWUGO, NULL, create_child);
+static DEVICE_ATTR(create_child, S_IWUSR, NULL, create_child);
 
 static ssize_t delete_child(struct device *dev,
 			    struct device_attribute *attr,
@@ -1183,7 +1183,7 @@ static ssize_t delete_child(struct device *dev,
 	return ret ? ret : count;
 
 }
-static DEVICE_ATTR(delete_child, S_IWUGO, NULL, delete_child);
+static DEVICE_ATTR(delete_child, S_IWUSR, NULL, delete_child);
 
 int ipoib_add_pkey_attr(struct net_device *dev)
 {