[ofa-general] Re: A question about rdma_get_cm_event

[Steve Wise]

Sean Hefty wrote:
>> When one calls to rdma_get_cm_event, he gets a structure of the 
>> rdma_cm_event.
>>
>> In this structure there are 2 attributes which i want to discuss about:
>> * private_data
>> * private_data_len
>>
>> It seems that when one side send to the other private data, the 
>> private data is correct
>> (i mean that the attribute private data points to a memory buffer with 
>> the expected data)
>> but the private_data_len has a fixed size (depend on the ucma function 
>> which was called).
>>
>> 1) Is this is the expected behavior?
> 
> Yes - there's no way for the receiving side of an IB CM message to know 
> how many bytes of private data are valid in the REQ, REP, etc.
> 
>> 2) can you please add entry to the man pages of this function to 
>> clarify this expected
>>     content of those attributes?
> 
> I will update the man pages.  Thanks.
>

Note that the private data length _is_ correct for iwarp.  So the man 
pages should mention that this is an IB-only issue maybe?  And maybe 
indicate that transport-independent applications should not rely on the 
length...

Steve.