Re: [PATCH 5/6] block: add zone attr. to zone mgmt IOCTL struct

[Damien Le Moal <Damien.LeMoal@wdc.com>]

On 2020/06/25 21:22, Javier González wrote:
> From: Javier González <javier.gonz@samsung.com>
> 
> Add zone attributes field to the blk_zone structure. Use ZNS attributes
> as base for zoned block devices in general.
> 
> Signed-off-by: Javier González <javier.gonz@samsung.com>
> Signed-off-by: SelvaKumar S <selvakuma.s1@samsung.com>
> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
> Signed-off-by: Nitesh Shetty <nj.shetty@samsung.com>
> ---
>  drivers/nvme/host/zns.c       |  1 +
>  include/uapi/linux/blkzoned.h | 13 ++++++++++++-
>  2 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/zns.c b/drivers/nvme/host/zns.c
> index 258d03610cc0..7d8381fe7665 100644
> --- a/drivers/nvme/host/zns.c
> +++ b/drivers/nvme/host/zns.c
> @@ -195,6 +195,7 @@ static int nvme_zone_parse_entry(struct nvme_ns *ns,
>  	zone.capacity = nvme_lba_to_sect(ns, le64_to_cpu(entry->zcap));
>  	zone.start = nvme_lba_to_sect(ns, le64_to_cpu(entry->zslba));
>  	zone.wp = nvme_lba_to_sect(ns, le64_to_cpu(entry->wp));
> +	zone.attr = entry->za;
>  
>  	return cb(&zone, idx, data);
>  }
> diff --git a/include/uapi/linux/blkzoned.h b/include/uapi/linux/blkzoned.h
> index 0c49a4b2ce5d..2e43a00e3425 100644
> --- a/include/uapi/linux/blkzoned.h
> +++ b/include/uapi/linux/blkzoned.h
> @@ -82,6 +82,16 @@ enum blk_zone_report_flags {
>  	BLK_ZONE_REP_CAPACITY	= (1 << 0),
>  };
>  
> +/**
> + * Zone Attributes

This is a user interface file. Please document the meaning of each attribute.

> + */
> +enum blk_zone_attr {
> +	BLK_ZONE_ATTR_ZFC	= 1 << 0,
> +	BLK_ZONE_ATTR_FZR	= 1 << 1,
> +	BLK_ZONE_ATTR_RZR	= 1 << 2,
> +	BLK_ZONE_ATTR_ZDEV	= 1 << 7,
These are ZNS specific, right ? Integrating the 2 ZBC/ZAC attributes in this
list would be nice, namely non_seq and reset. That will imply patching sd.c.

> +};
> +
>  /**
>   * struct blk_zone - Zone descriptor for BLKREPORTZONE ioctl.
>   *
> @@ -108,7 +118,8 @@ struct blk_zone {
>  	__u8	cond;		/* Zone condition */
>  	__u8	non_seq;	/* Non-sequential write resources active */
>  	__u8	reset;		/* Reset write pointer recommended */
> -	__u8	resv[4];
> +	__u8	attr;		/* Zone attributes */
> +	__u8	resv[3];
>  	__u64	capacity;	/* Zone capacity in number of sectors */
>  	__u8	reserved[24];
>  };
> 

You are missing a BLK_ZONE_REP_ATTR report flag to indicate to the user that the
attr field is present, used and valid.

enum blk_zone_report_flags {
 	BLK_ZONE_REP_CAPACITY	= (1 << 0),
+	BLK_ZONE_REP_ATTR	= (1 << 1),
 };

is I think needed.

-- 
Damien Le Moal
Western Digital Research