Date: Thu, 26 Mar 2015 15:13:34 -0600
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Michael Wang <yun.wang@profitbricks.com>
Cc: Doug Ledford <dledford@redhat.com>, linux-rdma@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org,
        netdev@vger.kernel.org, Roland Dreier <roland@kernel.org>,
        Sean Hefty <sean.hefty@intel.com>,
        Hal Rosenstock <hal.rosenstock@gmail.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Trond Myklebust <trond.myklebust@primarydata.com>,
        "J. Bruce Fields" <bfields@fieldses.org>,
        "David S. Miller" <davem@davemloft.net>,
        Moni Shoua <monis@mellanox.com>, Or Gerlitz <ogerlitz@mellanox.com>,
        Tatyana Nikolova <Tatyana.E.Nikolova@intel.com>,
        Steve Wise <swise@opengridcomputing.com>,
        Yan Burman <yanb@mellanox.com>,
        Jack Morgenstein <jackm@dev.mellanox.co.il>,
        Bart Van Assche <bvanassche@acm.org>,
        Yann Droneaud <ydroneaud@opteya.com>,
        Colin Ian King <colin.king@canonical.com>,
        Jiri Kosina <jkosina@suse.cz>, Matan Barak <matanb@mellanox.com>,
        Majd Dibbiny <majd@mellanox.com>,
        Dan Carpenter <dan.carpenter@oracle.com>, Mel Gorman <mgorman@suse.de>,
        Alex Estrin <alex.estrin@intel.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>, Tom Tucker <tom@ogc.us>,
        Chuck Lever <chuck.lever@oracle.com>
Subject: Re: [PATCH 0/2 RESEND] IB/Verbs: Use helpers to refine the checking
 on transport and link layer
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On Thu, Mar 26, 2015 at 05:58:20PM +0100, Michael Wang wrote:

> The questions is just wondering how the transition method could be, but
> if we have to do the changes for vendor, that sounds like a tough job...

I would see changing how the information is represented in the struct
as a follow on issue. The first patch should go through and replace
all direct access to the link layer/transport/etc with an
appropriately narrow is_XX() test like Doug was suggesting.

That means looking at each code site and determining what it needs,
making a is_XX for it and a kdoc describing exactly what is needed for
the test to return true.

The follow on patch can then rework the is_XX and drop the link
layer/transport stuff..

Some ideas for is_XX:
  IB compatible SA
  QP0 SMP mechanism
  IB SMP format
  OPA SMP format
  QP1 GMP mechanism
  IB compatible CM
  GID addressing
  IP/IPv6 addressing
  Ethernet VLAN
  ...

Jason