[openib-general] ipoib ipv6 multicast joins, was: multicast code/merge status

[Hal Rosenstock]

On Thu, 2007-01-11 at 19:11, Sean Hefty wrote: 
> Hal Rosenstock wrote:
> >>(*) there are some more issues here which need to be addressed, see
> >>for example the "Some SMs don't support send-only yet" weird comment
> >>at ipoib_mcast_sendonly_join()
> > 
> > 
> > It's more likely an SA issue but I'm only guessing... It may also be
> > historical...
> 
> Based on observation, it looks like ipoib joins a couple of IPv6 multicast 
> groups with send only membership.

Yes.

> However it changes the join_state from 4 to 1 
> (send-only to full member).

Yes, that is the workaround Roland had put in (likely for a non
compliant SM which didn't support send only joins).

> This results in the SA trying to create the 
> multicast group, only the required MCMemberRecord components have not been set.

Right, the group either needs to be previously precreated or a receiver
"started" first which would create the group.

> I'm not sure if this indicates a serious problem, but I'm guessing not.

I don't believe it's a serious problem (at least now). In any case, it
is no worse than it was before your change for this (it is not a problem
of your making...).

> The join request simply fails and returns an error back to ipoib.  (Which would have 
> happened for a send-only join if the group hadn't already been created.)

Right.

-- Hal

> - Sean