Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
Sender: Corey Minyard <tcminyard@gmail.com>
Date:   Wed, 1 Jun 2022 19:32:44 -0500
From:   Corey Minyard <minyard@acm.org>
To:     Quan Nguyen <quan@os.amperecomputing.com>
Cc:     devicetree@vger.kernel.org, linux-aspeed@lists.ozlabs.org,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Andrew Jeffery <andrew@aj.id.au>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        openbmc@lists.ozlabs.org,
        "Thang Q . Nguyen" <thang@os.amperecomputing.com>,
        Brendan Higgins <brendanhiggins@google.com>,
        linux-kernel@vger.kernel.org,
        Phong Vo <phong@os.amperecomputing.com>,
        Wolfram Sang <wsa@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        openipmi-developer@lists.sourceforge.net,
        Open Source Submission <patches@amperecomputing.com>,
        linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org
Subject: Re: [Openipmi-developer] [PATCH v7 1/3] ipmi: ssif_bmc: Add SSIF BMC
 driver
Message-ID: <20220602003244.GK3767252@minyard.net>
Reply-To: minyard@acm.org
References: <20220422040803.2524940-1-quan@os.amperecomputing.com>
 <20220422040803.2524940-2-quan@os.amperecomputing.com>
 <20220423015119.GE426325@minyard.net>
 <ec7b86ec-827f-da64-8fd2-eae09f802694@os.amperecomputing.com>
 <20220504120631.GE3767252@minyard.net>
 <ba084735-0781-7ca2-4d04-a70a4115729a@os.amperecomputing.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ba084735-0781-7ca2-4d04-a70a4115729a@os.amperecomputing.com>
Precedence: bulk

On Wed, Jun 01, 2022 at 03:23:11PM +0700, Quan Nguyen wrote:
> On 04/05/2022 19:06, Corey Minyard wrote:
> > On Wed, May 04, 2022 at 01:45:03PM +0700, Quan Nguyen via Openipmi-developer wrote:
> > > > 
> > > > I seem to remember mentioning this before, but there is no reason to
> > > > pack the structures below.
> > > > 
> > > 
> > > The packed structure is because we want to pick the len directly from user
> > > space without worry about the padding byte.
> > > 
> > > As we plan not to use the .h file in next version, I still would like to use
> > > packed structure internally inside ssif_bmc.c file.
> > 
> > Packed doesn't matter for the userspace API.  If you look at other
> > structures in the userspace API, they are not packed, either.  The
> > compiler will do the right thing on both ends.
> > 
> > > 
> > > > And second, the following is a userspace API structures, so it needs to
> > > > be in its own file in include/uapi/linux, along with any supporting
> > > > things that users will need to use.  And your userspace code should be
> > > > using that file.
> > > > 
> > > 
> > > Meantime, I'd like not to use .h as I see there is no demand for sharing the
> > > data structure between kernel and user space yet. But we may do it in the
> > > future.
> > 
> > If you have a userspace API, it needs to be in include/uapi/linux.
> > You may not be the only user of this code.  In fact, you probably won't
> > be.  You need to have a .h with the structures in it, you don't want the
> > same structure in two places if you can help it.
> > 
> 
> Dear Corey,
> 
> Is it OK to push the structure definition into the
> include/uapi/linux/ipmi_bmc.h ?
> 
> Or should it need to be in separate new header file in uapi/linux ?

I think a different file, like ipmi_ssif_bmc, to match the file and
operation.  Unless you need the things in ipmi_bmc.h, which I don't
think is the case.

-corey

> 
> Thank you,
> - Quan
> 
>