Re: [PATCH v5 1/5] ublk: add opcode offsets for DRV_IN/DRV_OUT

[Damien Le Moal <dlemoal@kernel.org>]

On 7/5/23 01:52, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@samsung.com>
> 
> Ublk zoned storage support relies on DRV_IN handling for zone report.
> Prepare for this change by adding offsets for the DRV_IN/DRV_OUT commands.
> 
> Also add parenthesis to existing opcodes for better macro hygiene.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
> ---
>  include/uapi/linux/ublk_cmd.h | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> index 4b8558db90e1..a32810c8ef2b 100644
> --- a/include/uapi/linux/ublk_cmd.h
> +++ b/include/uapi/linux/ublk_cmd.h
> @@ -229,12 +229,16 @@ 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
> +#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)

I do not think that adding the parenthesis is useful given that the values are
all constants.

> +#define		__UBLK_IO_OP_DRV_IN_START	(32)
> +#define		__UBLK_IO_OP_DRV_IN_END		(96)
> +#define		__UBLK_IO_OP_DRV_OUT_START	(__UBLK_IO_OP_DRV_IN_END)
> +#define		__UBLK_IO_OP_DRV_OUT_END	(160)

While the UBLK_IO_OP_XXX definitions are fairly obvious from their name, these
are much less obvious. A comment before these __UBLK_IO_OP_XXX would be welcome
to describe what these operations are.

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

-- 
Damien Le Moal
Western Digital Research