[openib-general][PATCH][kdapl]: evd upcall policy implementation

[Guy German]

James Lentini <mailto:jlentini at netapp.com> wrote:
>> You changed the order in which the CQ upcall is enabled and the kDAPL
>> upcall is made. It used to be:
>> 
>>  enable CQ upcall
>>  call kDAPL upcall
>> 
>> you are proposing
>> 
>>  call kDAPL upcall
>>  enable CQ upcall
>> 
>> I think your proposed order contains a race condition. Specifically
>> if a work completion occurs after dapl_evd_upcall_trigger()
>> returns but before the CQ upcall is re-enabled with
>> ib_req_notify_cq(), no upcall will occur for the completion.
>> 
>> Do you agree?

Or, has turned my attention to the fact that also in the first case
You have the alleged race: if a work completion occurs just
before you enable the CQ upcall...
Are you suggesting that enabling the CQ upcall will not trigger the
CQ upcall, if completions happened before enabling? 
I don't think this is the case, but I'm not 100% sure...

As I mentioned before, and regardless to this issue, I still believe 
that the right order should be:
>>  call kDAPL upcall
>>  (conditionally) enable CQ upcall
We can't have interrupts if the consumer disabled the upcall policy...

Guy.