tree 9bb255d9f596ab062996de49032875e8b9253971
parent ad643f54c8514998333bc6c7b201fda2267496be
author Dan Williams <dan.j.williams@intel.com> 1252436509 -0700
committer Dan Williams <dan.j.williams@intel.com> 1252456224 -0700

ioat: switch watchdog and reset handler from workqueue to timer

In order to support dynamic resizing of the descriptor ring or polling
for a descriptor in the presence of a hung channel the reset handler
needs to make progress while in a non-preemptible context.  The current
workqueue implementation precludes polling channel reset completion
under spin_lock().

This conversion also allows us to return to opportunistic cleanup in the
ioat2 case as the timer implementation guarantees at least one cleanup
after every descriptor is submitted.  This means the worst case
completion latency becomes the timer frequency (for exceptional
circumstances), but with the benefit of avoiding busy waiting when the
lock is contended.

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