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Message-ID: <4d75c340-0942-44cf-67db-ee52f58ee65e@intel.com>
Date:   Wed, 7 Dec 2022 17:27:18 -0700
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Subject: Re: [PATCH] cxl/uapi: Add warning on CXL command enum
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To:     ira.weiny@intel.com, Dan Williams <dan.j.williams@intel.com>
Cc:     Alison Schofield <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20221208000141.701642-1-ira.weiny@intel.com>
From:   Dave Jiang <dave.jiang@intel.com>
In-Reply-To: <20221208000141.701642-1-ira.weiny@intel.com>
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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>

> ---
>   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