[ofw] choice between IBAL and winverbs

[Sean Hefty]

Some of this has been answered, but to clarify...

>In WINOF 2.1, most of the ULPs are based on Winverbs, while IPoIB driver
>continues to use IBAL .

IBAL provides the only interface for kernel ULPs.  There has been a few requests
for a winverbs kernel interface that ULPs could eventually migrate to, but no
work has started on it. 

There are multiple userspace interfaces available: winverbs, libibverbs, dapl,
ND, and ibal.  All of these will be supported going forward, though the
underlying implementations may change/simplify.

>I wish to know if OFED will continue to support and enhance IBAL as
>complimentary approach for Winverbs for IB verbs interface ?  Or IBAL
>may be phased out ?

I don't think that any decision has been reached on this.  Personally, I believe
that there should eventually be a single kernel interface for the ULPs that more
closely matches up with Windows (i.e. something more like winverbs).  However, a
driver (e.g. IBAL) would still need to implement QP0/1 support and the related
clients, like the CM.  The winverbs interfaces as defined were not designed for
this purpose.

- Sean