From mboxrd@z Thu Jan  1 00:00:00 1970
From: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Subject: Re: [PATCH v1 1/4] net/mlx4: move rdma-core calls to
 separate file
Date: Thu, 25 Jan 2018 12:31:41 +0100
Message-ID: <20180125113141.GO4256@6wind.com>
References: <20180124223625.1928-1-adrien.mazarguil@6wind.com>
 <20180124223625.1928-2-adrien.mazarguil@6wind.com>
 <20180124155857.52457b9d@xeon-e3>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Shahaf Shuler <shahafs@mellanox.com>,
 Nelio Laranjeiro <nelio.laranjeiro@6wind.com>, dev@dpdk.org,
 Marcelo Ricardo Leitner <mleitner@redhat.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Return-path: <dev-bounces@dpdk.org>
Received: from mail-wm0-f68.google.com (mail-wm0-f68.google.com [74.125.82.68])
 by dpdk.org (Postfix) with ESMTP id 1A7E12BB5
 for <dev@dpdk.org>; Thu, 25 Jan 2018 12:31:55 +0100 (CET)
Received: by mail-wm0-f68.google.com with SMTP id r78so14330239wme.0
 for <dev@dpdk.org>; Thu, 25 Jan 2018 03:31:55 -0800 (PST)
Content-Disposition: inline
In-Reply-To: <20180124155857.52457b9d@xeon-e3>
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On Wed, Jan 24, 2018 at 03:58:57PM -0800, Stephen Hemminger wrote:
> On Thu, 25 Jan 2018 00:25:00 +0100
> Adrien Mazarguil <adrien.mazarguil@6wind.com> wrote:
> 
> > +const struct mlx4_glue *mlx4_glue = &(const struct mlx4_glue){
> > +	.fork_init = mlx4_glue_fork_init,
> > +	.get_async_event = mlx4_glue_get_async_event,
> 
> The cast should not be necessary here.

It's not a mere cast but a compound literal. The mlx4_glue symbol represents
a pointer to this structure, not the structure itself. This syntax is
equivalent to:

 static const struct mlx4_glue mlx4_glue_internal = {
    ...
 };

 const struct mlx4_glue *mlx4_glue = &mlx4_glue_internal;

The reason I chose to expose a pointer instead of that structure directly is
seamless transition to dlsym() in the next patch, otherwise all
mlx4_glue->foo() need to be first written mlx4_glue.foo() and then modified
as mlx4_glue->foo().

-- 
Adrien Mazarguil
6WIND