Re: [PATCH v6 1/3] ublk: add opcode offsets for DRV_IN/DRV_OUT

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

On 7/6/23 22:09, 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 | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> index 4b8558db90e1..2ebb8d5d827a 100644
> --- a/include/uapi/linux/ublk_cmd.h
> +++ b/include/uapi/linux/ublk_cmd.h
> @@ -229,12 +229,22 @@ struct ublksrv_ctrl_dev_info {
>  	__u64   reserved2;
>  };
>  
> -#define		UBLK_IO_OP_READ		0
> +#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_DISCARD		3
> +#define		UBLK_IO_OP_WRITE_SAME		4
> +#define		UBLK_IO_OP_WRITE_ZEROES		5
> +/*
> + * Passthrough (driver private) operation codes range between

This is unclear... Here, what does "driver" refer to ? If it is the ublk
kernel driver, than these commands should not be defined in the uapi
header file, they should be defined in drivers/block/ublk.h. However, if
these are for the user space driver, like all the other operations, then
let's clearly state so. But then, I still not understand why these need
a different naming pattern using the "__UBLK" prefix...

> + * __UBLK_IO_OP_DRV_IN_START and __UBLK_IO_OP_DRV_IN_END for REQ_OP_DRV_IN type
> + * operations and between __UBLK_IO_OP_DRV_OUT_START and
> + * __UBLK_IO_OP_DRV_OUT_END for REQ_OP_DRV_OUT type operations.
> + */
> +#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
>  
>  #define		UBLK_IO_F_FAILFAST_DEV		(1U << 8)
>  #define		UBLK_IO_F_FAILFAST_TRANSPORT	(1U << 9)

-- 
Damien Le Moal
Western Digital Research