gallium: cached bufmgr add map busy check

Suggested by Jose on the list, probably not perfect but will let me get
past this for now, testing with a fenced bufmgr on top of this, was slower,

Also this doesn't let you do the busy early exit optimisation either from
what I can see.

Signed-off-by: Dave Airlie <airlied@redhat.com>
1 file changed