This is a revised patch to fix a problem in the UHCI driver, in which the
compiler incorrectly optimizes certain accesses to DMA-able memory
addresses.  The patch reorganizes the code to use special accessor
routines including a compiler optimization barrier, and stores the results
in local variables to help prevent repeated accesses.  No use is made of
the "volatile" keyword.  :-)
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>