[ofa-general] Re: [PATCHv4 RFC] Scalable Reliable Connection: API and documentation

[Roland Dreier]

 > Having looked at implementation issues, it will be much simpler to just, as you say,
 > mimic the consumer API -- in kernel space as well.

Yes, in fact I think we might be able to get away with not breaking
the user-kernel ABI.  If I understand things correctly, XRC QPs do not
have an SRQ attached to them, so we could overload the srq_handle
member of struct ib_uverbs_create_qp to hold the xrc_domain_handle
when creating an XRC QP.

Then if we're OK with having create_xrc_srq be a separate operation
from create_srq, I think everything else doesn't break the ABI.

Does that seem like a good plan?  The only ugly thing is making the
interface a little fatter than it needs to be with the duplicated
create_xrc_srq and create_srq operations; but we save the pain of
bumping the ABI and avoid the ugliness of putting generic objects into
the driver-specific data (which would force us to export the lookup of
XRC objects from the uverbs module, etc).

 - R.