[PATCH 0/4] allow drivers to flush in-flight DMA

[akepner@sgi.com]

This is a followup to http://lkml.org/lkml/2007/8/24/280

Despite Grant's desire for a more elegant solution, there's 
not much new here. I moved the API change from pci.h to 
dma-mapping.h and removed the pci_ prefix from the name. 

Problem Description
-------------------
On Altix, DMA may be reordered within the NUMA interconnect.
This can be a problem with Infiniband, where DMA to Completion Queues 
allocated in user-space can race with data DMA. This patchset allows 
a driver to associate a user-space memory region with a "dmaflush" 
attribute, so that writes to the memory region flush in-flight DMA, 
preventing the CQ/data race.

There are four patches in this set:

  [1/4] dma: add dma_flags_set_dmaflush() to dma interface
  [2/4] dma: redefine dma_flags_set_dmaflush() for sn-ia64
  [3/4] dma: document dma_flags_set_dmaflush()
  [4/4] mthca: allow setting "dmaflush" attribute on user-allocated memory