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

Liran Liss
2016-05-24T16:02:04Z

> From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-
> owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Hefty, Sean
...
>
> The following is a sketch, or outline, for an ioctl framework.
> The purpose of the patch is to drive discussion and feedback on various design
> decisions rather than low-level comments on the code, so that the changes can
> be incorporated earlier in the development cycle. The code is entirely untested
> and some functionality is not coded.
>

This approach focuses on facilities for arbitrary device-specific objects (which could basically fit GPUs, NVMe, whatever...), while our primary goals are to replace write() with ioctl() and strive for a common *rdma* object model.

In contrast, the patchset [1], focuses on the task at hand. The emphasis is on a common framework for parsing and parameter validation. It follows the agreed-upon concepts such as a single ioctl request code for common objects, natural mapping of the existing object mode (and hence easier backporting), typed attributes for extending the objects to accommodate multiple vendor features, and a unique ioctl request code for vendor-specific commands.
--Liran

[1] http://permalink.gmane.org/gmane.linux.drivers.rdma/36984