Re: [PATCH v4 1/4] ublk: change ublk IO command defines to enum

[Damien Le Moal]

On 6/29/23 04:06, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> 
> This change is in preparation for zoned storage support.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
> ---
>  include/uapi/linux/ublk_cmd.h | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)
> 
> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> index 4b8558db90e1..471b3b983045 100644
> --- a/include/uapi/linux/ublk_cmd.h
> +++ b/include/uapi/linux/ublk_cmd.h
> @@ -229,12 +229,23 @@ struct ublksrv_ctrl_dev_info {
>  	__u64   reserved2;
>  };
>  
> -#define		UBLK_IO_OP_READ		0
> -#define		UBLK_IO_OP_WRITE		1
> -#define		UBLK_IO_OP_FLUSH		2
> -#define		UBLK_IO_OP_DISCARD	3
> -#define		UBLK_IO_OP_WRITE_SAME	4
> -#define		UBLK_IO_OP_WRITE_ZEROES	5
> +enum ublk_op {
> +	UBLK_IO_OP_READ = 0,
> +	UBLK_IO_OP_WRITE = 1,
> +	UBLK_IO_OP_FLUSH = 2,
> +	UBLK_IO_OP_DISCARD = 3,
> +	UBLK_IO_OP_WRITE_SAME = 4,
> +	UBLK_IO_OP_WRITE_ZEROES = 5,
> +	UBLK_IO_OP_ZONE_OPEN = 10,
> +	UBLK_IO_OP_ZONE_CLOSE = 11,
> +	UBLK_IO_OP_ZONE_FINISH = 12,
> +	UBLK_IO_OP_ZONE_APPEND = 13,
> +	UBLK_IO_OP_ZONE_RESET = 15,
> +	__UBLK_IO_OP_DRV_IN_START = 32,
> +	__UBLK_IO_OP_DRV_IN_END = 96,
> +	__UBLK_IO_OP_DRV_OUT_START = __UBLK_IO_OP_DRV_IN_END,
> +	__UBLK_IO_OP_DRV_OUT_END = 160,
> +};

This patch does not do what the title says. You are also introducing the zone
operations, and the very obscure __UBLK_IO_OP_DRV_XXX operations without an
explanation. Also, why the "__" prefix for these ? I do not see the point...
Given that this is a uapi, a comment to explain the less obvious commands would
be nice.

So I think the change to an enum for the existing ops can be done either in
patch 2 or as a separate patch and the introduction of the zone operations done
in patch 3 or as a separate patch.

>  
>  #define		UBLK_IO_F_FAILFAST_DEV		(1U << 8)
>  #define		UBLK_IO_F_FAILFAST_TRANSPORT	(1U << 9)

-- 
Damien Le Moal
Western Digital Research