Re: [PATCH] cxl/uapi: Add warning on CXL command enum

[Dave Jiang]

On 12/7/2022 5:01 PM, ira.weiny@xxxxxxxxx wrote:
> From: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> 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@xxxxxxxxx>
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>

Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>

> ---
>   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