[openib-general] change req_notify_cq to return void

[Michael S. Tsirkin]

Hi!
According to IB spec, the output modifiers of req_notify_cq are:

. Verb Results:
. Operation completed successfully.
. Invalid HCA handle.
. Invalid CQ handle.
. Invalid completion notification type.

In other words, there's no way req_notify_cq can fail.
I propose changing the function return type to void and so
save consumers the need to check it.

Does this make sense to people here?

-- 
MST - Michael S. Tsirkin