Re: [PATCH V2] ublk: zoned: support REQ_OP_ZONE_RESET_ALL

[Niklas Cassel <Niklas.Cassel@wdc.com>]

On Thu, Aug 10, 2023 at 08:43:26PM +0800, Ming Lei wrote:
> There isn't any reason to not support REQ_OP_ZONE_RESET_ALL given everything
> is actually handled in userspace, not mention it is pretty easy to support
> RESET_ALL.
> 
> So enable REQ_OP_ZONE_RESET_ALL and let userspace handle it.
> 
> Verified by 'tools/zbc_reset_zone -all /dev/ublkb0' in libzbc[1] with
> libublk-rs based ublk-zoned target prototype[2], follows command line
> for creating ublk-zoned:
> 
> 	cargo run --example zoned -- add -1 1024	# add $dev_id $DEV_SIZE
> 
> [1] https://github.com/westerndigitalcorporation/libzbc
> [2] https://github.com/ming1/libublk-rs/tree/zoned.v2
> 
> Cc: Niklas Cassel <Niklas.Cassel@wdc.com>
> Cc: Damien Le Moal <dlemoal@kernel.org>
> Cc: Andreas Hindborg <a.hindborg@samsung.com>
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
> V2:
> 	- update comment as reported by Niklas
> 
>  drivers/block/ublk_drv.c      | 7 +++++--
>  include/uapi/linux/ublk_cmd.h | 1 +
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index b60394fe7be6..3650ef209344 100644
> --- a/drivers/block/ublk_drv.c
> +++ b/drivers/block/ublk_drv.c
> @@ -251,6 +251,7 @@ static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
>  	const struct ublk_param_zoned *p = &ub->params.zoned;
>  
>  	disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
> +	blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, ub->ub_disk->queue);
>  	blk_queue_required_elevator_features(ub->ub_disk->queue,
>  					     ELEVATOR_F_ZBD_SEQ_WRITE);
>  	disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
> @@ -393,6 +394,9 @@ static blk_status_t ublk_setup_iod_zoned(struct ublk_queue *ubq,
>  	case REQ_OP_ZONE_APPEND:
>  		ublk_op = UBLK_IO_OP_ZONE_APPEND;
>  		break;
> +	case REQ_OP_ZONE_RESET_ALL:
> +		ublk_op = UBLK_IO_OP_ZONE_RESET_ALL;
> +		break;
>  	case REQ_OP_DRV_IN:
>  		ublk_op = pdu->operation;
>  		switch (ublk_op) {
> @@ -404,9 +408,8 @@ static blk_status_t ublk_setup_iod_zoned(struct ublk_queue *ubq,
>  		default:
>  			return BLK_STS_IOERR;
>  		}
> -	case REQ_OP_ZONE_RESET_ALL:
>  	case REQ_OP_DRV_OUT:
> -		/* We do not support reset_all and drv_out */
> +		/* We do not support drv_out */
>  		return BLK_STS_NOTSUPP;
>  	default:
>  		return BLK_STS_IOERR;
> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
> index 2685e53e4752..b9cfc5c96268 100644
> --- a/include/uapi/linux/ublk_cmd.h
> +++ b/include/uapi/linux/ublk_cmd.h
> @@ -245,6 +245,7 @@ struct ublksrv_ctrl_dev_info {
>  #define		UBLK_IO_OP_ZONE_CLOSE		11
>  #define		UBLK_IO_OP_ZONE_FINISH		12
>  #define		UBLK_IO_OP_ZONE_APPEND		13
> +#define		UBLK_IO_OP_ZONE_RESET_ALL	14

For some reason, it seems like the UBLK_IO_OP_ZONE_* values
are identical to the REQ_OP_ZONE_* values in enum req_op:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/blk_types.h?h=v6.5-rc5#n371

I don't see any obvious advantage of keeping them the same,
but if you want to keep this pattern, then perhaps you want
to define UBLK_IO_OP_ZONE_RESET_ALL to 17.


Kind regards,
Niklas