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From: Brian Norris <briannorris@chromium.org>
To: shuah <shuah@kernel.org>
Cc: David Valleau <valleau@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux USB Mailing List <linux-usb@vger.kernel.org>,
	Michael Grzeschik <m.grzeschik@pengutronix.de>,
	Valentina Manea <valentina.manea.m@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <alexander.levin@microsoft.com>
Subject: Re: [PATCH] tools: usb: usbip: adding support for older kernel versions
Date: Mon, 18 Mar 2019 11:23:22 -0700	[thread overview]
Message-ID: <CA+ASDXMcnEfZzTjDGsDbZxX2Xknv6dt3H-3kN79WdKFzif2zsA@mail.gmail.com> (raw)
In-Reply-To: <44e151af-b6c4-d0af-3ef1-a5632d079915@kernel.org>

On Sat, Mar 16, 2019 at 4:40 PM shuah <shuah@kernel.org> wrote:
> usbip tool is tied to the kernel version. This is reason why it is
> co-located with the usbip driver in the kernel sources. This is not
> a typical tool scenario to be able to use new tool on old kernels.
>
> I would like to understand the reasons for wanting to run new tool on
> old kernels.

On Chromium OS, we ship more or less the same user space for a variety
of systems, but not all of those run the same kernel. That's not
exactly a novel concept -- many good tools are written such that they
degrade gracefully when running with reduced feature sets (e.g., older
kernels). While we are working on reducing the divergence and number
of kernels we ship, it's currently a fact of life that we have to
support multiple target kernel versions.

Is there a fundamental problem with VHCI such that it doesn't have a
stable ABI that tools can be written against?

If stability is possible but you just don't care, then I guess we can
fork our own version...

Or even worse, we could build N copies of usbip for N kernels. But we
don't do that for any other user space component.

Brian

WARNING: multiple messages have this Message-ID (diff)
From: Brian Norris <briannorris@chromium.org>
To: shuah <shuah@kernel.org>
Cc: David Valleau <valleau@chromium.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux USB Mailing List <linux-usb@vger.kernel.org>,
	Michael Grzeschik <m.grzeschik@pengutronix.de>,
	Valentina Manea <valentina.manea.m@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <alexander.levin@microsoft.com>
Subject: tools: usb: usbip: adding support for older kernel versions
Date: Mon, 18 Mar 2019 11:23:22 -0700	[thread overview]
Message-ID: <CA+ASDXMcnEfZzTjDGsDbZxX2Xknv6dt3H-3kN79WdKFzif2zsA@mail.gmail.com> (raw)

On Sat, Mar 16, 2019 at 4:40 PM shuah <shuah@kernel.org> wrote:
> usbip tool is tied to the kernel version. This is reason why it is
> co-located with the usbip driver in the kernel sources. This is not
> a typical tool scenario to be able to use new tool on old kernels.
>
> I would like to understand the reasons for wanting to run new tool on
> old kernels.

On Chromium OS, we ship more or less the same user space for a variety
of systems, but not all of those run the same kernel. That's not
exactly a novel concept -- many good tools are written such that they
degrade gracefully when running with reduced feature sets (e.g., older
kernels). While we are working on reducing the divergence and number
of kernels we ship, it's currently a fact of life that we have to
support multiple target kernel versions.

Is there a fundamental problem with VHCI such that it doesn't have a
stable ABI that tools can be written against?

If stability is possible but you just don't care, then I guess we can
fork our own version...

Or even worse, we could build N copies of usbip for N kernels. But we
don't do that for any other user space component.

Brian

  reply	other threads:[~2019-03-18 18:23 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-06 21:47 [PATCH] tools: usb: usbip: adding support for older kernel versions David Valleau
2019-03-06 21:47 ` David Valleau
2019-03-16 23:39 ` [PATCH] " shuah
2019-03-16 23:39   ` Shuah Khan
2019-03-18 18:23   ` Brian Norris [this message]
2019-03-18 18:23     ` Brian Norris
2019-03-25 15:51     ` [PATCH] " shuah
2019-03-25 15:51       ` Shuah Khan
2019-03-25 17:56       ` [PATCH] " Brian Norris
2019-03-25 17:56         ` Brian Norris
2019-03-25 22:07         ` [PATCH] " shuah
2019-03-25 22:07           ` Shuah Khan
2019-03-25 23:02           ` [PATCH] " Brian Norris
2019-03-25 23:02             ` Brian Norris
2019-03-26  0:04             ` [PATCH] " shuah
2019-03-26  0:04               ` Shuah Khan
2019-03-26  1:29               ` [PATCH] " Brian Norris
2019-03-26  1:29                 ` Brian Norris
2019-03-26  1:59                 ` [PATCH] " shuah
2019-03-26  1:59                   ` Shuah Khan
2019-03-27  1:16                   ` [PATCH] " Brian Norris
2019-03-27  1:16                     ` Brian Norris
2019-03-26  0:13             ` [PATCH] " Greg Kroah-Hartman
2019-03-26  0:13               ` Greg Kroah-Hartman
2019-03-26  0:49               ` [PATCH] " Brian Norris
2019-03-26  0:49                 ` Brian Norris
2019-03-26  0:55                 ` [PATCH] " Greg Kroah-Hartman
2019-03-26  0:55                   ` Greg Kroah-Hartman
2019-03-26  1:28                   ` [PATCH] " Brian Norris
2019-03-26  1:28                     ` Brian Norris

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