A patch series for next that removes a substantial number of read-modify-write operations from TTM command submission, in particular if TTM objects are used to export objects to user-space. The only per-object atomic r-m-w operations left during a typical execbuf call should be refcount up and down.
v2: Formatting fixes.
v3: Invert the return value of kref_get_unless_zero.
Add a comment in the commit message to patch 4 that it may be obsoleted.
