[openib-general] [CM] [patch] add a check that paths are reversible when connecting RC QPs

[Michael S. Tsirkin]

> Quoting r. Dotan Barak <dotanb at dev.mellanox.co.il>:
> Subject: Re: [CM] [patch] add a check that paths are reversible when connecting RC QPs
> 
> Sean Hefty wrote:
> 
> > Dotan Barak wrote:
> >
> >> +    if (!param->primary_path->reversible && param->qp_type == IB_QPT_RC)
> >> +        return -EINVAL;
> >
> >
> > Why did you include a check for the qp_type?
> 
> Because one can use a UC QP as a sender only sending any ack (at least 
> on this QP).

Correct. A separate QP can be used for communication and this is
something that e.g. IPoIB CM on top of UC would want to do.

> But to be honest, i have a second thought on the check of the transport 
> type of the QP:
> maybe the CM should deny any setting of non reversible path for any QP,
> to let know the user that there may be a problem with this path ...
> 
> what do you think?

IMO, we don't really need this to check user paths, strictly speaking - we can't
validate all fields, anyway.  So unless this checking can be made to work
without limiting potentially useful functionality, let's just drop the
patch.

-- 
MST