I seem to have lost this read_unlock().

While we're there, let's turn that interruptible sleep unto uninterruptible,
so we don't get a busywait if signal_pending().  (Again.  We seem to have a
habit of doing this).
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>