Re: [PATCH v2 1/8] cxl/mem: Move some definitions to mem.h

From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Dan Williams <dan.j.williams@intel.com>
Cc: <linux-cxl@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	"Linux ACPI" <linux-acpi@vger.kernel.org>,
	"Weiny, Ira" <ira.weiny@intel.com>,
	"Vishal L Verma" <vishal.l.verma@intel.com>,
	"Schofield, Alison" <alison.schofield@intel.com>,
	Ben Widawsky <ben.widawsky@intel.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/8] cxl/mem: Move some definitions to mem.h
Date: Wed, 14 Apr 2021 10:21:15 +0100	[thread overview]
Message-ID: <20210414102115.00001f09@Huawei.com> (raw)
In-Reply-To: <CAPcyv4iueMDPxcEuLg=NKydkRL+xmEn-udHjKYB493iTQShaAg@mail.gmail.com>

On Tue, 13 Apr 2021 17:42:37 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> On Tue, Apr 13, 2021 at 5:18 PM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > On Tue, Apr 6, 2021 at 10:47 AM Jonathan Cameron
> > <Jonathan.Cameron@huawei.com> wrote:  
> > >
> > > On Thu, 1 Apr 2021 07:30:47 -0700
> > > Dan Williams <dan.j.williams@intel.com> wrote:
> > >  
> > > > In preparation for sharing cxl.h with other generic CXL consumers,
> > > > move / consolidate some of the memory device specifics to mem.h.
> > > >
> > > > Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
> > > > Signed-off-by: Dan Williams <dan.j.williams@intel.com>  
> > >
> > > Hi Dan,
> > >
> > > Would be good to see something in this patch description saying
> > > why you chose to have mem.h rather than push the defines down
> > > into mem.c (which from the current code + patch set looks like
> > > the more logical thing to do).  
> >
> > The main motivation was least privilege access to memory-device
> > details, so they had to move out of cxl.h. As to why move them in to a
> > new mem.h instead of piling more into mem.c that's just a personal
> > organizational style choice to aid review. I tend to go to headers
> > first and read data structure definitions before reading the
> > implementation, and having that all in one place is cleaner than
> > interspersed with implementation details in the C code. It's all still
> > private to drivers/cxl/ so I don't see any "least privilege" concerns
> > with moving it there.
> >
> > Does that satisfy your concern?
> >
> > If yes, I'll add the above to v3.  
> 
> Oh, another thing it helps is the information content of diffstats to
> distinguish definition changes from implementation development.

I go the other way style wise, but agree it doesn't really matter for
local headers included from few other files.  Adding a above to
comment will at least avoid anyone else (or forgetful me) raising question on v3.

Jonathan