[PATCH] knfsd: nfsd4: create separate laundromat workqueue

We're running the laundromat work on the default kevent worker thread.  But
the laundromat takes the nfsv4 state semaphore, which is used for way too much
stuff, and the potential for deadlocks is high.  Better to have this on a
separate workqueue.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>