RE: [RFC] rdma/uverbs: Sketch for an ioctl framework

Hefty, Sean
2016-05-24T22:38:58Z

> > Under that model, each vendor only carries what they need. It would
> > then be libibverbs responsibility to take that driver specific data
> > and
>
> Either patchset could go in this direction. This is a basic question
> we need to decide on.
>
> I'm starting to think the basic thrust of the Mellanox series (provide
> an easy compatability with our userspace) is a sane approach. The
> other options look like far too much work to use as a starting point.

What matters is whether the work needs to be done anyway, and how can we get to the end design. I don’t see a time crunch to force switching to ioctls.

> You are the only person I've heard who wants to restructure the
> libibverbs interface at the same time..
>
> When I kicked off this process at the OFA meeting the discussions
> revolved around some very clear goals:
> 1) Comprehensively close the security issue
> 2) Provide 100% support for existing libibverbs users on the current
> libibverbs API
> 3) Restructure obvious known weaknesses (eg IB specific areas)
> 4) Add additional extension points

I still don't think we even have agreement on what this interface should be. There is not a single user space library that's being targeted here. If the only goal is to support libibverbs, then we need another option for devices that are not verbs based, but expose hardware specific structures to user space. This is why you see objections to putting this under uverbs. Non-verbs use cases keep getting completely overlooked in the conversation.