Hi!
As mentioned in the patch description, there is a conflict in license, That is why, I have avoided to put any of them in the header. Once confirmed within the community, I can add the original license here. (GPL2.1+) as https://github.com/linux-test-project/ltp/wiki/Test-Writing-Guidelines this says only to add code with GPL2.0+.
As far as I can tell there is no GPL2.1+ the only 2.1 version in existence is LGPL.
GPL2.1+ usually happens to be an error when someone takes library header with LGPL2.1+ license and removes the "Lesser" part.
However it looks like the whole libhugetlbfs is under LGPL2.1+ which kind of makes sense for a library, but not so much for the tests since these do not provide a library that can be linked againts at all.