[ofa-general] hang on close in umem_release

[Roland Dreier]

 > Looks obviously correct and tests okay.  Ctrl-c in any situation
 > does the right thing now.  Before your refactoring of ib_umem, the
 > older version of ib_umem_release_on_close() did not have this
 > trylock optimization.  This new buggy code appears not to have shown
 > up in any releases yet, fortunately.

Thanks, I will add it to my queue of things to get Linus to pull soon.

It is true that this was introduced by my recent refactoring -- a
silly careless mistake.

 - R.