[openib-general] port space

[Sean Hefty]

Eric Barton wrote:
> 1. Am I correct to think rdma_listen() will listen on ALL HCAs/ports unless I
>    first bind it to a specific IP address?  Can I enumerate these IP addresses
>    beforehand (other than by SIOCGIFADDR on "ib*").

Listen will listen across all HCAs/ports.  There's no simply way that I'm aware 
of to enumerate the IP addresses.

> 2. Does the 'backlog' parameter to rdma_listen() do anything?  I see
>    rdma_listen() set id_priv->backlog from it, but that seems to be after it
>    could have been used.

It depends on the underlying transport.  For IB, backlog is not used in the 
kernel.  For iWarp, it will be.  It does end up being used for userspace apps 
for any transport.

> 3. I'm not sure I understand enum rdma_port_space.  Is it just there to carve
>    up the service number space between different ULPs?  If I use RDMA_PS_TCP,
>    will this not conflict potentially with IPoIB sockets?

To your first question, yes, but it ends up being needed by iWarp.  For your 
second question, that is still TBD.  The port number assignment still needs 
work, but there port space sharing between that used by the rdma cm and sockets 
is currently undefined.  For IB, there is no sharing, but for iWarp there will be.

Sorry, this probably doesn't help you much.  What are your requirements for how 
the port space should behave?

- Sean