[openib-general] [PATCH] use mmiowb after doorbell ring

[Roland Dreier]

OK, you convinced me to add rmb()/wmb() and use it in libmthca.  I
just checked a bunch of changes to do that into svn.  Please survey
the wreckage of libibverbs/libmthca and let me know if you see where I
broke anything.

For now I just used lock; addl %0 to implement rmb on i386.  I'm
really not comfortable making libmthca depend on sse2, and I don't see
a good way to detect and use sse2 at runtime.

Thanks,
  Roland