[openib-general] Re: device add/remove in userspace

[Sean Hefty]

Tom Tucker wrote:
> I'm not sure of all the issues you're considering, but it seems to me at
> first blush that the user space stuff should talk the kernel CMA. If you
> don't do it in the kernel: 
> - you will end up replicating transport dependent connection management
> logic in the user mode library 
> - you will have to export, support and maintain a much larger number of
> kernel services
> - implementing security/provisioning policy in user mode is trickier
> than in the kernel

My hope is that the userspace CMA can talk to the kernel CMA.  Otherwise, I need 
to expose the kernel address translation and SA query services, plus deal with 
more complicated event handling.

The issue is that the kernel CMA performs QP transitions, which would need to 
change for userspace QPs.  To transition the QPs properly, the userspace CMA 
would need to do so based on IB CM messages, and not kernel CMA events.

- Sean