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Date:   Thu, 17 Feb 2022 07:13:44 +0100
From:   Greg KH <gregkh@linuxfoundation.org>
To:     Guixin Liu <kanie@linux.alibaba.com>
Cc:     bostroesser@gmail.com, martin.petersen@oracle.com,
        linux-scsi@vger.kernel.org, target-devel@vger.kernel.org,
        linux-kernel@vger.kernel.org, xiaoguang.wang@linux.alibaba.com,
        xlpang@linux.alibaba.com
Subject: Re: [PATCH 1/2] uio: add ioctl to uio
Message-ID: <Yg3nmK7iWp7FuoOa@kroah.com>
References: <1645064962-94123-1-git-send-email-kanie@linux.alibaba.com>
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On Thu, Feb 17, 2022 at 10:29:21AM +0800, Guixin Liu wrote:
> In TCMU, if backstore holds its own userspace buffer, for read cmd, the
> data needs to be copied from userspace buffer to tcmu data area first,
> and then needs to be copied from tcmu data area to scsi sgl pages again.
> 
> To solve this problem, add ioctl to uio to let userspace backstore can
> copy data between scsi sgl pages and its own buffer directly.
> 
> Reviewed-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
> Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
> ---
>  drivers/uio/uio.c          | 22 ++++++++++++++++++++++
>  include/linux/uio_driver.h |  1 +

No, sorry, thie uio driver will not be adding ioctls to them.  If you
need an ioctl, then you should not be using the UIO api but rather use a
custom character driver instead.

thanks,

greg k-h