[ofa-general] Re: [PATCH 3/3 v4] ib/ipoib: blocking multicast loopback ipoib packets

[Or Gerlitz]

On 7/4/08, Roland Dreier <rdreier at cisco.com> wrote:
>   Hmm, I missed the original email.
>   Anyway I have no idea how to do the block multicast feature really.  I thought there was > some idea that userspace would pass QP creation flags into the kernel?

 yes,  this was one  idea (earlier one that is a new QP type eg
IB_QPT_UD_BML) and the thing is that we  would be happy to get your
take on how can this be done with minimum pain regarding ABI issues
both up towards libibverbs consumers and down towards ib_uverbs.

Actually, looking on the XRC patch set, as it adds new QP type anyway,
 IB_QPT_UD_BML might turn to be the simplest way here, but its not
general enough as moving forward, people were talking on other create
flags they want to use from user space (low latency QP, etc)

>  Was there some reason that XRC wanted to use QP creation flags too?

 Among other things, the XRC patch series adds the
"ibv_create_xrc_rcv_qp"  new verb to libibverbs, so my thought here
was that a new way X to create QPs is added, and we want a new way Y
for the block multicast loop. So maybe we can form a framework Z for
creating QPs other then the old one. Alternatively its possible for
the create_qp_with_create_flags verb (and other verbs we want to add
such as cq_modify_moderation_params) to just live next to the new
verbs added to libibverbs in the new ibv_xrc_ops structure which is
added for the verbs context.

thoughts?

Or.