Slightly delayed, but here is loop-5. It's against 2.4.2-pre4, as
testing on 2.4.1-ac19 showed other problems (oom killer would kill
dbench or bash before it could finish...). I'll take a look at ac19
next. Changes since loop-4:

o Make sure loop_thread is up. A mount -o loop could sometimes sneak
  in a request before the helper thread was started. (me)

o Remove all the backing file setup, count on get_file just
  holding a reference to it. (Neil Brown)

o Remove fs/buffer.c:wakeup_bdflush work around. loop doesn't block
  on requests, so it shouldn't be needed.

*.kernel.org/pub/linux/kernel/people/axboe/patches/2.4.2-pre4/loop-5

--
Jens Axboe