[PATCH] Add locking to dpt(4)

[John Baldwin]

I have patches to add locking to dpt(4) and make it MPSAFE (along with some 
other fixes).  I would appreciate any testing folks are able to do.  The 
patches are against HEAD but should apply to 8 or 9.  Please ensure you have 
INVARIANTS and INVARIANT_SUPPORT enabled for any initial testing that you do.  
Thanks!

http://www.FreeBSD.org/~jhb/patches/dpt_locking.patch

-- 
John Baldwin