tree c64b4585518028b5c8ae749b93d9f560d536f649
parent 7b3cc2b1fc2066391e498f3387204908c4eced21
author Dan Williams <dan.j.williams@intel.com> 1258675863 -0700
committer Dan Williams <dan.j.williams@intel.com> 1258698063 -0700

ioat3: fix pq completion versus channel deallocation race

The completion of a pq operation is notified with a null descriptor
appended to the end of the chain.  This descriptor needs to be visible
to dma clients otherwise the client is precluded from ensuring all
operations are quiesced before freeing channel resources, i.e. due to
descriptor polling it may get the completion notification ahead of the
interrupt delivered by the null descriptor.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>