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Date:   Thu, 8 Dec 2022 10:41:45 +0000
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     Dave Jiang <dave.jiang@intel.com>
CC:     <ira.weiny@intel.com>, Dan Williams <dan.j.williams@intel.com>,
        "Alison Schofield" <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        <linux-cxl@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] cxl/uapi: Add warning on CXL command enum
Message-ID: <20221208104145.000059a8@Huawei.com>
In-Reply-To: <4d75c340-0942-44cf-67db-ee52f58ee65e@intel.com>
References: <20221208000141.701642-1-ira.weiny@intel.com>
        <4d75c340-0942-44cf-67db-ee52f58ee65e@intel.com>
Organization: Huawei Technologies Research and Development (UK) Ltd.
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On Wed, 7 Dec 2022 17:27:18 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> On 12/7/2022 5:01 PM, ira.weiny@intel.com wrote:
> > From: Ira Weiny <ira.weiny@intel.com>
> > 
> > The CXL command enum is exported to user space and must maintain
> > backwards compatibility.
> > 
> > Add comment that new defines must be added to the end of the list.
> > 
> > Suggested-by: Dan Williams <dan.j.williams@intel.com>
> > Signed-off-by: Ira Weiny <ira.weiny@intel.com>  
> 
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Good to have.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> 
> > ---
> >   include/uapi/linux/cxl_mem.h | 4 ++++
> >   1 file changed, 4 insertions(+)
> > 
> > diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
> > index c71021a2a9ed..459a3f7f764b 100644
> > --- a/include/uapi/linux/cxl_mem.h
> > +++ b/include/uapi/linux/cxl_mem.h
> > @@ -19,6 +19,10 @@
> >   #define CXL_MEM_QUERY_COMMANDS _IOR(0xCE, 1, struct cxl_mem_query_commands)
> >   #define CXL_MEM_SEND_COMMAND _IOWR(0xCE, 2, struct cxl_send_command)
> >   
> > +/*
> > + * NOTE: New defines must be added to the end of the list to preserve
> > + * compatibility because this enum is exported to user space.
> > + */
> >   #define CXL_CMDS                                                          \
> >   	___C(INVALID, "Invalid Command"),                                 \
> >   	___C(IDENTIFY, "Identify Command"),                               \
> > 
> > base-commit: acb704099642bc822ef2aed223a0b8db1f7ea76e