From: Greg KH <gregkh@linuxfoundation.org>
To: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Cc: Bodo Stroesser <bostroesser@gmail.com>,
Guixin Liu <kanie@linux.alibaba.com>,
martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
target-devel@vger.kernel.org, linux-kernel@vger.kernel.org,
xlpang@linux.alibaba.com
Subject: Re: [PATCH 2/2] scsi:target:tcmu: reduce once copy by using uio ioctl
Date: Mon, 28 Feb 2022 11:47:13 +0100 [thread overview]
Message-ID: <YhyoMekPbsKjO7KG@kroah.com> (raw)
In-Reply-To: <4aef53b1-3e0f-92eb-4bd3-cdc4cd301866@linux.alibaba.com>
On Mon, Feb 28, 2022 at 04:52:52PM +0800, Xiaoguang Wang wrote:
>
> hi Bodo,
>
> > Liu,
> >
> > generally I like ideas to speed up tcmu.
> >
> > OTOH, since Andy Grover implemented tcmu based on uio device, we are
> > restricted to what uio offers. With today's knowledge I think we would
> > not use the uio device in tcmu again, but switching away from uio now
> > would break existing userspace SW.
> Yeah, it will have much work if deciding to switch away from uio.
> I came up with a hacky or crazy idea :) what about we create a new file
> in tcmu_open() by anon_inode_getfile_secure(), and export this fd by
> tcmu mail box, we can do ioctl() on this new file, then uio framework
> won't be touched...
No new ioctls please. That is creating a new user/kernel api that you
must support for the next 20+ years. Please do not do that.
thanks,
greg k-h
next prev parent reply other threads:[~2022-02-28 10:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 2:29 [PATCH 1/2] uio: add ioctl to uio Guixin Liu
2022-02-17 2:29 ` [PATCH 2/2] scsi:target:tcmu: reduce once copy by using uio ioctl Guixin Liu
2022-02-17 6:45 ` kernel test robot
2022-02-17 6:45 ` kernel test robot
2022-02-17 8:07 ` kernel test robot
2022-02-17 8:07 ` kernel test robot
2022-02-17 10:15 ` Greg KH
2022-02-17 11:13 ` Xiaoguang Wang
2022-02-17 12:28 ` Greg KH
2022-02-17 11:10 ` [RFC PATCH] scsi:target:tcmu: tcmu_ioctl_copy_between_sgl_and_iovec() can be static kernel test robot
2022-02-17 11:10 ` kernel test robot
2022-02-17 11:12 ` [PATCH 2/2] scsi:target:tcmu: reduce once copy by using uio ioctl kernel test robot
2022-02-17 11:12 ` kernel test robot
2022-02-21 17:09 ` Bodo Stroesser
2022-02-28 8:52 ` Xiaoguang Wang
2022-02-28 10:47 ` Greg KH [this message]
2022-02-17 6:13 ` [PATCH 1/2] uio: add ioctl to uio Greg KH
[not found] ` <362edb61-b8ad-495e-2346-8020355c0938@linux.alibaba.com>
2022-02-17 12:30 ` Greg KH
2022-02-17 12:30 ` Xiaoguang Wang
2022-02-17 6:55 ` kernel test robot
2022-02-17 6:55 ` kernel test robot
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