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From:   "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
To:     Ming Lei <tom.leiming@gmail.com>
Cc:     Ming Lei <ming.lei@redhat.com>,
        Christoph Hellwig <hch@infradead.org>, gost.dev@samsung.com,
        "open list:BLOCK LAYER" <linux-block@vger.kernel.org>,
        Hans Holmberg <Hans.Holmberg@wdc.com>,
        Matias Bjorling <Matias.Bjorling@wdc.com>,
        Minwoo Im <minwoo.im.dev@gmail.com>,
        Jens Axboe <axboe@kernel.dk>,
        Johannes Thumshirn <jth@kernel.org>,
        Aravind Ramesh <Aravind.Ramesh@wdc.com>,
        Damien Le Moal <dlemoal@kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v10 2/3] ublk: move check for empty address field on
 command submission
Date:   Fri, 04 Aug 2023 12:08:55 +0200
In-reply-to: <ZMy+dTpJzln7DlgZ@ovpn-8-25.pek2.redhat.com>
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Ming Lei <tom.leiming@gmail.com> writes:

> Hi Andreas,
>
> On Thu, Aug 03, 2023 at 04:07:00PM +0200, Andreas Hindborg (Samsung) wrot=
e:
>> From: Andreas Hindborg <a.hindborg@samsung.com>
>>=20
>> In preparation for zoned storage support, move the check for empty `addr`
>> field into the command handler case statement. Note that the check makes=
 no
>> sense for `UBLK_IO_NEED_GET_DATA` because the `addr` field must always be
>> set for this command.
>>=20
>> Signed-off-by: Andreas Hindborg <a.hindborg@samsung.com>
>> ---
>>  drivers/block/ublk_drv.c | 18 +++++++++++++-----
>>  1 file changed, 13 insertions(+), 5 deletions(-)
>>=20
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index db3523e281a6..5a1ee17636ac 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -1419,11 +1419,6 @@ static int __ublk_ch_uring_cmd(struct io_uring_cm=
d *cmd,
>>  			^ (_IOC_NR(cmd_op) =3D=3D UBLK_IO_NEED_GET_DATA))
>>  		goto out;
>>=20=20
>> -	if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
>> -		ret =3D -EINVAL;
>> -		goto out;
>> -	}
>> -
>>  	ret =3D ublk_check_cmd_op(cmd_op);
>>  	if (ret)
>>  		goto out;
>> @@ -1452,6 +1447,12 @@ static int __ublk_ch_uring_cmd(struct io_uring_cm=
d *cmd,
>>  				goto out;
>>  		}
>>=20=20
>> +		/* User copy requires addr to be unset */
>> +		if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
>> +			ret =3D -EINVAL;
>> +			goto out;
>> +		}
>> +
>
> Given you have to post v11 for fixing build issue, please convert the
> above two 'if' into one 'if else':
>
> 		if (!ublk_support_user_copy(ubq)) {
> 			/*
> 			 * FETCH_RQ has to provide IO buffer if NEED GET
> 			 * DATA is not enabled
> 			 */
> 			if (!ub_cmd->addr && !ublk_need_get_data(ubq))
> 				goto out;
> 		} else {
> 			if (ub_cmd->addr) {
> 				ret =3D -EINVAL;
> 				goto out;
> 			}
> 		}

Alright. I was debating with myself one over the other =F0=9F=98=85

>
>>  		ublk_fill_io_cmd(io, cmd, ub_cmd->addr);
>>  		ublk_mark_io_ready(ub, ubq);
>>  		break;
>> @@ -1470,6 +1471,13 @@ static int __ublk_ch_uring_cmd(struct io_uring_cm=
d *cmd,
>>  						req_op(req) =3D=3D REQ_OP_READ))
>>  				goto out;
>>  		}
>> +
>> +		/* User copy requires addr to be unset */
>> +		if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
>> +			ret =3D -EINVAL;
>> +			goto out;
>> +		}
>> +
>
> Same with above.
>
> BTW, I have verified this patchset with ublk-zoned example in
> libublk-rs:
>
> https://github.com/ming1/libublk-rs/tree/zoned.v2
>
> cargo run --example zoned -- add -1 10240
> mkfs.btrfs -O zoned /dev/ublkb0
> mount & git clone linux-kernel &umount

Thanks!

BR Andreas