On Tue, 2008-05-20 at 16:38 -0500, Scott Wood wrote:

It looks like we rely on -fno-strict-aliasing to prevent reordering 
ordinary memory accesses (such as to DMA descriptors) past the I/O 
access.  It won't prevent reordering of memory reads around an I/O
read, 
though, which could be a problem if the I/O read result determines
the 
validity of the DMA buffer.  IMHO, a memory clobber would be better.

We probably want a full "memory" clobber then...

Ben.