Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <d23bf48c-5bc9-aab6-4ca2-ebbb24a0878e@kernel.org>
Date:   Thu, 29 Jun 2023 07:47:47 +0900
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.12.0
Subject: Re: [PATCH v4 1/4] ublk: change ublk IO command defines to enum
To:     Andreas Hindborg <nmi@metaspace.dk>, Ming Lei <ming.lei@redhat.com>
Cc:     Hans Holmberg <Hans.Holmberg@wdc.com>,
        Aravind Ramesh <Aravind.Ramesh@wdc.com>,
        Jens Axboe <axboe@kernel.dk>,
        "open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
        Christoph Hellwig <hch@infradead.org>,
        Matias Bjorling <Matias.Bjorling@wdc.com>,
        Andreas Hindborg <a.hindborg@samsung.com>,
        open list <linux-kernel@vger.kernel.org>, gost.dev@samsung.com,
        Minwoo Im <minwoo.im.dev@gmail.com>
References: <20230628190649.11233-1-nmi@metaspace.dk>
 <20230628190649.11233-2-nmi@metaspace.dk>
Content-Language: en-US
From:   Damien Le Moal <dlemoal@kernel.org>
Organization: Western Digital Research
In-Reply-To: <20230628190649.11233-2-nmi@metaspace.dk>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 6/29/23 04:06, Andreas Hindborg wrote:
> From: Andreas Hindborg <a.hindborg@samsung.com>
> 
> This change is in preparation for zoned storage support.
> 
> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
> ---
>  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