[RFC] Adding private data and private data len as argument to rdma_disconnect()

[Anand Ashok Khoje <anand.a.khoje@oracle.com>]

Hi,

I just wanted to float an idea for an enhancement and get opinions.

There is a provision in ib_cm layer API ib_send_cm_dreq() to send a
private_data along with the DREQ.
This private_data is helpful in situations where the receiver of DREQ 
may want
to understand the reason for the DREQ and do some action on the basis of 
that
reason.
We have come across issues where it was critical for the RDS code to 
understand
the reason behind a DREQ and recover/tweak some parameters.

Now, rdma_cm layer has a wrapper around ib_send_cm_dreq() i.e 
rdma_disconnect().
rdma_disconnect() is used by the consumers of rdma_cm. rdma_disconnect() 
does
not have an argument that accepts private data. Due to this, consumers 
are not
able to use this feature.

In case if we add the arguments private_data and private_data_length to
rds_disconnect(), the only challenge would be to add those to the callers
of it (NULL and 0).

Please let me know your thoughts on this.

Thanks
Anand