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: <6723190a-e317-2161-d93e-71f8c2f88232@linux.alibaba.com>
Date:   Fri, 15 Jul 2022 14:07:17 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0)
 Gecko/20100101 Thunderbird/91.11.0
Subject: Re: [PATCH V5 1/2] ublk_drv: add io_uring based userspace block
 driver
Content-Language: en-US
To:     Ming Lei <ming.lei@redhat.com>
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        io-uring@vger.kernel.org, Jens Axboe <axboe@kernel.dk>,
        Gabriel Krisman Bertazi <krisman@collabora.com>,
        Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
References: <20220713140711.97356-1-ming.lei@redhat.com>
 <20220713140711.97356-2-ming.lei@redhat.com>
 <a4249561-84a0-a314-c377-b96d28b7b20b@linux.alibaba.com>
 <Ys/0jTxQCEHdI560@T590>
 <fe9508ae-f12a-2216-1160-145308d746f5@linux.alibaba.com>
 <YtDLSdwbV/utn0Qv@T590>
From:   Ziyang Zhang <ZiyangZhang@linux.alibaba.com>
In-Reply-To: <YtDLSdwbV/utn0Qv@T590>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 2022/7/15 10:04, Ming Lei wrote:
> On Thu, Jul 14, 2022 at 09:23:40PM +0800, Ziyang Zhang wrote:
>> On 2022/7/14 18:48, Ming Lei wrote:
>>> On Thu, Jul 14, 2022 at 06:20:38PM +0800, Ziyang Zhang wrote:
>>>> On 2022/7/13 22:07, Ming Lei wrote:
>>>>> This is the driver part of userspace block driver(ublk driver), the other
>>>>> part is userspace daemon part(ublksrv)[1].
>>>>>
...
>>
>> Put it together:
>>
>> When daemon is PF_EXITING:
>>
>> 1) current ublk_io: aborted immediately in task_work
> 
> Precisely it is just that ublk io request is ended immediately, so io->flags
> won't be touched.
> 
>>
>> 2) UBLK_IO_FLAG_ACTIVE set: aborted in ublk_daemon_monitor_work
> 
> This part is important for making forward progress, that is why it has
> to be done in a wq context.
> 
>>
>> 3) UBLK_IO_FLAG_ACTIVE unset: send cqe with UBLK_IO_RES_ABORT

Oh... sorry for one mistake. case 2) and 3) should be swapped:

ublk_daemon_monitor_work(): abort blk-mq IOs if UBLK_IO_FLAG_ACTIVE is unset

ublk_cancel_queue(): send cqes with UBLK_IO_RES_ABORT if UBLK_IO_FLAG_ACTIVE is set