[openib-general] [PATCH] ib_mad: Implementib_free_recv_mad routine

[Sean Hefty]

>> Actually, this change should decrease memory usage -- saves a whole
>> pointer.
>
>Isn't that only for the first buffer ? Don't buffers 2-n have an
>unneeded WC structure ?

I'm suggesting is that instead of the ib_mad_recv_wc pointing to the first
ib_mad_recv_buf structure, it contains it.  Buffers 2-n would still be
referenced by ib_mad_recv_buf structures chained off of the recv_buf in the
ib_mad_recv_wc.  The user would only receive on ib_mad_recv_wc.

>Also, do you see a way to turn a receive buffer handed to the client
>around ? That seems to be useful for the agents in order to respond to a
>request without copying into a send buffer.

As long as the user calls ib_free_recv_mad after the send operation
completes, they should be able to reuse the data buffer from the receive.
We could also give some thought to some sort of ib_reply_to_recv_mad()
routine that could take an ib_mad_recv_wc as input (with the buffer
modified) and generate a send to the source of the receive.  The call could
allocate an address handle, format a send work request, post the send, and
deallocate the address handle once the send completed.  Something like this
could easily enough be added on later though.