and another for dst descriptors. This provide partial solution to OB1 protocol
deadlock problem. We can limit number of RDMA descriptors (by setting
btl_openib_free_list_max to something different from -1) and if we will be
lucky to hit this limit before we fail to register more memory the protocol
will not deadlock. When we had only one list for src/dst descriptors we
deadlocked when we reached max limit for the list.
This commit was SVN r13844.