Date: Fri, 27 Mar 2015 11:47:27 -0600
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: "ira.weiny" <ira.weiny@intel.com>
Cc: Michael Wang <yun.wang@profitbricks.com>,
        Roland Dreier <roland@kernel.org>, Sean Hefty <sean.hefty@intel.com>,
        Hal Rosenstock <hal.rosenstock@gmail.com>, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
        netdev@vger.kernel.org, "J. Bruce Fields" <bfields@fieldses.org>,
        Trond Myklebust <trond.myklebust@primarydata.com>,
        "David S. Miller" <davem@davemloft.net>,
        Or Gerlitz <ogerlitz@mellanox.com>, Moni Shoua <monis@mellanox.com>,
        PJ Waskiewicz <pj.waskiewicz@solidfire.com>,
        Tatyana Nikolova <Tatyana.E.Nikolova@intel.com>,
        Yan Burman <yanb@mellanox.com>,
        Jack Morgenstein <jackm@dev.mellanox.co.il>,
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        Matan Barak <matanb@mellanox.com>, Alex Estrin <alex.estrin@intel.com>,
        Doug Ledford <dledford@redhat.com>, Eric Dumazet <edumazet@google.com>,
        Erez Shitrit <erezsh@mellanox.com>, Sagi Grimberg <sagig@mellanox.com>,
        Haggai Eran <haggaie@mellanox.com>,
        Shachar Raindel <raindel@mellanox.com>,
        Mike Marciniszyn <mike.marciniszyn@intel.com>,
        Steve Wise <swise@opengridcomputing.com>, Tom Tucker <tom@ogc.us>,
        Chuck Lever <chuck.lever@oracle.com>
Subject: Re: [RFC PATCH 07/11] IB/Verbs: Use management helper has_mcast()
 and, cap_mcast() for mcast-check
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On Fri, Mar 27, 2015 at 01:05:08PM -0400, ira.weiny wrote:

> > But it seems redudent, since mcast_add_one will already not add a port that is
> > not IB, so mcast_event_handler is not callable. Something to do with
> > rocee/ib switching?
> 
> I'm not sure about this either.  This check seems to be necessary only on a
> per-port level.  It does seem apparent that one can't go from Eth to IB.  What
> happens if you go from IB to Eth on the port?

Hmm... I see a mlx4_change_port_types which ultimately calls
ib_unregister_device, which suggests the port type doesn't change at
runtime (yay)

So maybe these checks really are redundant?

Jason