Currently the the SN2 dma mapping code uses a file systen lookup (cat /r/napali/tmp/p10 |diffstat -p1) to
find the operation vector for the underlying dma mapping implementation.

But not only there is exactly one of those implementation, also data
structures from this lowlevel driver are used in the actual Linux dma
mapping routines and quite a few assumption are made about it.  So let's
just call directly in the lowlevel code and give up this utter bullshit.