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From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>,
	"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>
Subject: Re: [PATCH] null_blk: poll queue support
Date: Mon, 20 Sep 2021 12:40:00 +0100	[thread overview]
Message-ID: <19eecc0f-c7d7-ef4d-3a79-74a57753a3a1@gmail.com> (raw)
In-Reply-To: <1002cd58-63b6-453a-93c0-774928690e5f@kernel.dk>

On 9/16/21 2:57 AM, Jens Axboe wrote:
> On 9/14/21 3:38 PM, Pavel Begunkov wrote:
>> On 4/17/21 4:29 PM, Jens Axboe wrote:
>>> There's currently no way to experiment with polled IO with null_blk,
>>> which seems like an oversight. This patch adds support for polled IO.
>>> We keep a list of issued IOs on submit, and then process that list
>>> when mq_ops->poll() is invoked.
>>
>> That would be pretty useful to have.
>>
>> to fold in:
>>
>> diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
>> index 5914fed8fa56..eb5cfe189e90 100644
>> --- a/drivers/block/null_blk/main.c
>> +++ b/drivers/block/null_blk/main.c
>> @@ -1508,7 +1508,7 @@ static int null_poll(struct blk_mq_hw_ctx *hctx)
>>  		cmd = blk_mq_rq_to_pdu(req);
>>  		cmd->error = null_process_cmd(cmd, req_op(req), blk_rq_pos(req),
>>  						blk_rq_sectors(req));
>> -		nullb_complete_cmd(cmd);
>> +		end_cmd(cmd);
>>  		nr++;
>>  	}
> 
> Let's try again with that...

I'm not so sure it fixes the problem Bart mentioned, but at least it
doesn't crash for me right away (timer mode) and io_uring tests complete
well.

-- 
Pavel Begunkov

      reply	other threads:[~2021-09-20 11:40 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-17 15:29 [PATCH] null_blk: poll queue support Jens Axboe
2021-04-18  4:48 ` Chaitanya Kulkarni
2021-04-18  4:49 ` Chaitanya Kulkarni
2021-04-19 19:48   ` Jens Axboe
2021-04-19 22:19     ` Chaitanya Kulkarni
2021-04-19 22:55       ` Jens Axboe
2021-05-03 15:47 ` Bart Van Assche
2021-05-03 17:42   ` Jens Axboe
2021-05-04  0:32     ` Bart Van Assche
2021-09-14 21:38 ` Pavel Begunkov
2021-09-16  1:57   ` Jens Axboe
2021-09-20 11:40     ` Pavel Begunkov [this message]

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