Add endpoint data structure for nvme API

[igaw]

The MI API uses the endpoint data struct to abstracts from implementation details. Introduce an similiar API for the nvme interface. The goal here is to decouple from the low level API and be able to mock certain APIs for testing.

[jk-ozlabs]

It would be great if we can use a common struct between the direct and MI interfaces - this means we could avoid duplicating the API for each transport.

I'm happy to propose something for this, if you like.

[igaw]

Sorry, for the late response. Public holiday :)

Let me have a look at it now. IIRC this work was depending on other work? Anyway, I'l review it now (coffee needed)

Yes, please. If you have something in mind I am glad to discuss it :)

BTW, I've planned this for v2.0 because I expected it to break the current API, but I might be wrong.

[jk-ozlabs]

Yes, this would be a fairly big change - it would alter the arguments for almost every function. Definitely something for a ABI-breaking milestone.

I'll put together some sketches for this.