[ofa-general] removing PR caching from IPoIB

[Roland Dreier]

 > My first thought was to tie the IPoIB PR lifetime to ipoib_neigh and
 > treat unicast ARPs separately.  For unicast ARPs, I was thinking of
 > setting the skb as the context of the PR query and send it after it
 > completed, but I hadn't considered cleanup.

So you would do a new path record lookup for every unicast ARP that
gets sent?  What is the advantage of that?

 > As an alternate approach, I could try adding a reference count to
 > ipoib_path that's incremented once for each neighbour or when sending
 > a unicast ARP.  This may be equivalent to merging ipoib_ah and
 > ipoib_path, but I haven't looked at the details of trying this.
 > 
 > Do you have a preference or any other suggestions that would limit the
 > PR lifetime?

What is the motivation for these changes?  If you explain what you're
trying to fix, then maybe I can give a more intelligent answer.

 - R.