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From: Ziyang Zhang <[email protected]>
To: Ming Lei <[email protected]>
Cc: [email protected],
	Miklos Szeredi <[email protected]>,
	Xiaoguang Wang <[email protected]>,
	Bernd Schubert <[email protected]>,
	Pavel Begunkov <[email protected]>,
	[email protected], Stefan Hajnoczi <[email protected]>,
	[email protected], Jens Axboe <[email protected]>,
	Dan Williams <[email protected]>
Subject: Re: [PATCH V5 16/16] block: ublk_drv: apply io_uring FUSED_CMD for supporting zero copy
Date: Wed, 29 Mar 2023 10:57:53 +0800	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On 2023/3/28 23:09, Ming Lei wrote:
> Apply io_uring fused command for supporting zero copy:
> 

[...]

>  
> @@ -1374,7 +1533,12 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
>  	if (!ubq || ub_cmd->q_id != ubq->q_id)
>  		goto out;
>  
> -	if (ubq->ubq_daemon && ubq->ubq_daemon != current)
> +	/*
> +	 * The fused command reads the io buffer data structure only, so it
> +	 * is fine to be issued from other context.
> +	 */
> +	if ((ubq->ubq_daemon && ubq->ubq_daemon != current) &&
> +			(cmd_op != UBLK_IO_FUSED_SUBMIT_IO))
>  		goto out;
>  

Hi Ming,

What is your use case that fused io_uring cmd is issued from another thread?
I think it is good practice to operate one io_uring instance in one thread
only.

Regards,
Zhang

  reply	other threads:[~2023-03-29  2:58 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-28 15:09 [PATCH V5 00/16] io_uring/ublk: add IORING_OP_FUSED_CMD Ming Lei
2023-03-28 15:09 ` [PATCH V5 01/16] io_uring: increase io_kiocb->flags into 64bit Ming Lei
2023-03-28 15:09 ` [PATCH V5 02/16] io_uring: add IORING_OP_FUSED_CMD Ming Lei
2023-03-28 17:33   ` kernel test robot
2023-03-28 15:09 ` [PATCH V5 03/16] io_uring: support normal SQE for fused command Ming Lei
2023-03-28 15:09 ` [PATCH V5 04/16] io_uring: support OP_READ/OP_WRITE for fused secondary request Ming Lei
2023-03-28 15:09 ` [PATCH V5 05/16] io_uring: support OP_SEND_ZC/OP_RECV " Ming Lei
2023-03-28 15:09 ` [PATCH V5 06/16] block: ublk_drv: add common exit handling Ming Lei
2023-03-28 15:09 ` [PATCH V5 07/16] block: ublk_drv: don't consider flush request in map/unmap io Ming Lei
2023-03-28 15:09 ` [PATCH V5 08/16] block: ublk_drv: add two helpers to clean up map/unmap request Ming Lei
2023-03-28 15:09 ` [PATCH V5 09/16] block: ublk_drv: clean up several helpers Ming Lei
2023-03-28 15:09 ` [PATCH V5 10/16] block: ublk_drv: cleanup 'struct ublk_map_data' Ming Lei
2023-03-28 15:09 ` [PATCH V5 11/16] block: ublk_drv: cleanup ublk_copy_user_pages Ming Lei
2023-03-28 15:09 ` [PATCH V5 12/16] block: ublk_drv: grab request reference when the request is handled by userspace Ming Lei
2023-03-28 15:09 ` [PATCH V5 13/16] block: ublk_drv: support to copy any part of request pages Ming Lei
2023-03-28 15:09 ` [PATCH V5 14/16] block: ublk_drv: add read()/write() support for ublk char device Ming Lei
2023-03-28 15:09 ` [PATCH V5 15/16] block: ublk_drv: don't check buffer in case of zero copy Ming Lei
2023-03-28 15:09 ` [PATCH V5 16/16] block: ublk_drv: apply io_uring FUSED_CMD for supporting " Ming Lei
2023-03-29  2:57   ` Ziyang Zhang [this message]
2023-03-29  9:00     ` Ming Lei
2023-03-29 10:01       ` Ziyang Zhang
2023-03-29 10:52         ` Ming Lei
2023-04-03  8:38           ` Ziyang Zhang
2023-04-03  9:22             ` Ming Lei

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