[PATCH v6 0/5] tools/usbip: Patch set summary

[PATCH v6 0/5] tools/usbip: Patch set summary

[Lars Gunnarsson]

To forward a remote usb device over usbip the following steps is required:

1. Execute "usbip bind" on remote end.
2. Execute "usbip attach" on local end.

These steps must be perfomed in above order and after usb device is plugged in.
If the usb device is unplugged on the remote end the steps above needs to be
performed again to establish the connection. This patch set implements a feature
to persistently forward devices on a given bus. When using flag "-p|--persistent"
on remot end, the USB device becomes exported when plugged in. When using flag
"-p|--persistent" on local end, the USB device becomes imported when available
on remote end. Thus it is only required to run the usbip command once on each
end, in any order, to persistently forward usb devices on a given bus.

This is sent in five separate patches:
  tools/usbip: update protocol documentation
  tools/usbip: update manual pages
  tools/usbip: add usb event monitor into libusbip
  tools/usbip: export USB devices on a given bus persistently
  tools/usbip: import USB devices on a given bus persistently

Re: [PATCH v6 0/5] tools/usbip: Patch set summary

[Greg KH]

On Tue, Nov 30, 2021 at 11:22:54PM +0100, Lars Gunnarsson wrote:
> To forward a remote usb device over usbip the following steps is required:
> 
> 1. Execute "usbip bind" on remote end.
> 2. Execute "usbip attach" on local end.
> 
> These steps must be perfomed in above order and after usb device is plugged in.
> If the usb device is unplugged on the remote end the steps above needs to be
> performed again to establish the connection. This patch set implements a feature
> to persistently forward devices on a given bus. When using flag "-p|--persistent"
> on remot end, the USB device becomes exported when plugged in. When using flag
> "-p|--persistent" on local end, the USB device becomes imported when available
> on remote end. Thus it is only required to run the usbip command once on each
> end, in any order, to persistently forward usb devices on a given bus.
> 
> This is sent in five separate patches:
>   tools/usbip: update protocol documentation
>   tools/usbip: update manual pages
>   tools/usbip: add usb event monitor into libusbip
>   tools/usbip: export USB devices on a given bus persistently
>   tools/usbip: import USB devices on a given bus persistently

Oh wow, this patch series subject lines and threading is crazy, there is
no way to figure out what is going on here.

This is what this series looks like in my mailbox:

	Nov 30 Lars Gunnarsson ( 479) [PATCH v4 5/5] tools/usbip: import USB devices on a given bus persistentl
	Nov 30 Lars Gunnarsson ( 206) [PATCH v5 4/5] tools/usbip: export USB devices on a given bus persistentl
	Nov 30 Lars Gunnarsson ( 292) [PATCH v4 3/5] tools/usbip: add usb event monitor into libusbip
	Nov 30 Lars Gunnarsson (  86) [PATCH v2 2/5] tools/usbip: update manual pages
	Nov 30 Lars Gunnarsson ( 118) [PATCH v3 1/5] tools/usbip: update protocol documentation
	Nov 30 Lars Gunnarsson (  20) [PATCH v6 0/5] tools/usbip: Patch set summary


You have a mix of "v" levels and nothing is threaded at all, showing
what patch is related to what.  Look at the lore.kernel.org link for
this, which shows none of the patches in the series:
	https://lore.kernel.org/all/20211130222254.GA16447@dell-precision-T3610/

Please use tools like 'git send-email' and 'git format-patch' to send
and create patches if you don't want to do it by hand as they will
handle the threading and versioning properly for you automatically.

Here's how a patch series looks in my mailbox that was done correctly as
contrast:

	Nov 24 Prashant Malani (  34) [PATCH 0/4] usb: Use notifier for linking Type C ports.
	Nov 26 Heikki Krogerus (  32) ├─>
	Nov 30 Heikki Krogerus (  40) │ └─>
	Nov 30 Prashant Malani (  57) │   └─>
	Dec 01 Heikki Krogerus (  77) │     └─>
	Nov 24 Prashant Malani ( 109) ├─>[PATCH 1/4] usb: typec: Add port registration notifier
	Nov 24 Prashant Malani ( 114) │ └─>
	Nov 24 Prashant Malani ( 199) ├─>[PATCH 2/4] usb: Use notifier to link Type C ports
	Nov 25 kernel test rob (  55) │ └─>
	Nov 24 Prashant Malani (  92) ├─>[PATCH 4/4] Revert "usb: Iterator for ports"
	Nov 24 Prashant Malani (  60) └─>[PATCH 3/4] usb: Link the ports to the connectors they are attached t

See how the patches are linked together?  That is because the correct
"In-Reply-To:" lines are being set.

Please fix up and resend as a "v7" patch series for ALL patches (patch
versions are for the whole series, not for individual patches, otherwise
it is crazy to try to track...)

thanks,

greg k-h

Re: [PATCH v6 0/5] tools/usbip: Patch set summary

[Shuah Khan]

On 11/30/21 3:22 PM, Lars Gunnarsson wrote:
> To forward a remote usb device over usbip the following steps is required:
> 
> 1. Execute "usbip bind" on remote end.
> 2. Execute "usbip attach" on local end.
> 
> These steps must be perfomed in above order and after usb device is plugged in.
> If the usb device is unplugged on the remote end the steps above needs to be
> performed again to establish the connection. This patch set implements a feature
> to persistently forward devices on a given bus. When using flag "-p|--persistent"
> on remot end, the USB device becomes exported when plugged in. When using flag
> "-p|--persistent" on local end, the USB device becomes imported when available
> on remote end. Thus it is only required to run the usbip command once on each
> end, in any order, to persistently forward usb devices on a given bus.
> 
> This is sent in five separate patches:
>    tools/usbip: update protocol documentation
>    tools/usbip: update manual pages
>    tools/usbip: add usb event monitor into libusbip
>    tools/usbip: export USB devices on a given bus persistently
>    tools/usbip: import USB devices on a given bus persistently
> 

When -p is used, the command stays in foreground. This is a very
different use model compared to current model. In addition, once
persistent flag is set on a bus, all devices even the ones that
are inserted in the future get exported. What happens if one of
the devices shouldn't be exported?

There are several conditions to be thought through:

- What happens if if the command that is running on the foreground
   is killed on either end?
- What happens when one or more devices are detached?
- What happens when one or more devices are unbound from
   the server?

Let's walk through these scenarios.

thanks,
-- Shuah

Re: [PATCH v6 0/5] tools/usbip: Patch set summary

[Lars Gunnarsson]

On Mon, Dec 06, 2021 at 01:02:35PM -0700, Shuah Khan wrote:
> On 11/30/21 3:22 PM, Lars Gunnarsson wrote:
> > To forward a remote usb device over usbip the following steps is required:
> > 
> > 1. Execute "usbip bind" on remote end.
> > 2. Execute "usbip attach" on local end.
> > 
> > These steps must be perfomed in above order and after usb device is plugged in.
> > If the usb device is unplugged on the remote end the steps above needs to be
> > performed again to establish the connection. This patch set implements a feature
> > to persistently forward devices on a given bus. When using flag "-p|--persistent"
> > on remot end, the USB device becomes exported when plugged in. When using flag
> > "-p|--persistent" on local end, the USB device becomes imported when available
> > on remote end. Thus it is only required to run the usbip command once on each
> > end, in any order, to persistently forward usb devices on a given bus.
> > 
> > This is sent in five separate patches:
> >    tools/usbip: update protocol documentation
> >    tools/usbip: update manual pages
> >    tools/usbip: add usb event monitor into libusbip
> >    tools/usbip: export USB devices on a given bus persistently
> >    tools/usbip: import USB devices on a given bus persistently
> > 
> 
> When -p is used, the command stays in foreground. This is a very
> different use model compared to current model. In addition, once
> persistent flag is set on a bus, all devices even the ones that
> are inserted in the future get exported. What happens if one of
> the devices shouldn't be exported?

Yes it's conceptually more like exporting/importing the physical usb port,
rather than exporting/importing a device plugged into the usb port. Using flag
"-p" on both ends will behave like a "virtual" usb hub, a device plugged in on
the server (on a chosen bus) will automatically be available on the client.
Using flag "-p" has no dependency on the other end though. Using "-p" on one end
doesn't enforce usage on the other end. It is only for exporting and importing
devices automatically when they become available.

There might be better choices than naming flag to "persistent" for easily
communicate this concept. Would "port" be more intuitive?
"usbip attach --port 3-3.1" and "usbip bind --port 3-3.1"

> 
> There are several conditions to be thought through:
> 
> - What happens if if the command that is running on the foreground
>   is killed on either end?

If "attach" cmd gets killed (client side) it will stop the foreground
monitoring. The device will still remain imported if user exit at imported state.
The user then needs to manually unimport the device with "detach".

If "bind" cmd gets killed (server side) it will stop the foreground monitoring.
The device will still remain exported if exit at exported state. The user then
needs to manually unexport the device with "unbind".

> - What happens when one or more devices are detached?

If user exit from "attach" cmd running in foreground, followed by detaching the
device manually, it will work as previously. The device will become available on
the server for importing again.

If user running "attach" cmd in foreground, while executing "detach" manually
from another terminal or similar, the foreground "attach" command will detect
the disconnection and re-establish the import. I don't see any use case for
this, it's just for explaining.

If user running "attach" cmd in foreground, while the remote device becomes
unexported (or disconnected) it will start polling the usbipd.
When a device becomes exported on the chosen bus it gets imported immediately.

> - What happens when one or more devices are unbound from
>   the server?
> 
> Let's walk through these scenarios.

If user exit from "bind" cmd running in foreground, followed by unbind the
device manually it will work as previous. The usb device will become available
on the server again.

If user running "bind" cmd in foreground, while executing "unbind" from another
terminal or similar, the foreground "bind" command will detect the unexport
and re-establish the export. I don't see any use case for this, it's just for
explaining.

If user running "bind" cmd in foreground, while the device becomes unexported
or disconnected it will restart monitoring the busid. When a device becomes
plugged in on the chosen usb port it gets exported immediately.

One option to consider is to unexport & unimport the device at exit, but this
comes with the cost of creating a source code dependency between
bind --> unbind and attach --> detach.

Best regards, Lars

> 
> thanks,
> -- Shuah
> 
> 

Re: [PATCH v6 0/5] tools/usbip: Patch set summary

[Shuah Khan]

On 12/9/21 2:11 PM, Lars Gunnarsson wrote:
> On Mon, Dec 06, 2021 at 01:02:35PM -0700, Shuah Khan wrote:
>> On 11/30/21 3:22 PM, Lars Gunnarsson wrote:
>>> To forward a remote usb device over usbip the following steps is required:
>>>
>>> 1. Execute "usbip bind" on remote end.
>>> 2. Execute "usbip attach" on local end.
>>>
>>> These steps must be perfomed in above order and after usb device is plugged in.
>>> If the usb device is unplugged on the remote end the steps above needs to be
>>> performed again to establish the connection. This patch set implements a feature
>>> to persistently forward devices on a given bus. When using flag "-p|--persistent"
>>> on remot end, the USB device becomes exported when plugged in. When using flag
>>> "-p|--persistent" on local end, the USB device becomes imported when available
>>> on remote end. Thus it is only required to run the usbip command once on each
>>> end, in any order, to persistently forward usb devices on a given bus.
>>>
>>> This is sent in five separate patches:
>>>     tools/usbip: update protocol documentation
>>>     tools/usbip: update manual pages
>>>     tools/usbip: add usb event monitor into libusbip
>>>     tools/usbip: export USB devices on a given bus persistently
>>>     tools/usbip: import USB devices on a given bus persistently
>>>
>>
>> When -p is used, the command stays in foreground. This is a very
>> different use model compared to current model. In addition, once
>> persistent flag is set on a bus, all devices even the ones that
>> are inserted in the future get exported. What happens if one of
>> the devices shouldn't be exported?
> 
> Yes it's conceptually more like exporting/importing the physical usb port,
> rather than exporting/importing a device plugged into the usb port. Using flag
> "-p" on both ends will behave like a "virtual" usb hub, a device plugged in on
> the server (on a chosen bus) will automatically be available on the client.
> Using flag "-p" has no dependency on the other end though. Using "-p" on one end
> doesn't enforce usage on the other end. It is only for exporting and importing
> devices automatically when they become available.
> 
> There might be better choices than naming flag to "persistent" for easily
> communicate this concept. Would "port" be more intuitive?
> "usbip attach --port 3-3.1" and "usbip bind --port 3-3.1"
> 

Terminology isn't what I am concerned about. My concern is the idea of
automatically making devices available for export at bus level.

>>
>> There are several conditions to be thought through:
>>
>> - What happens if if the command that is running on the foreground
>>    is killed on either end?
> 
> If "attach" cmd gets killed (client side) it will stop the foreground
> monitoring. The device will still remain imported if user exit at imported state.
> The user then needs to manually unimport the device with "detach".
> 
> If "bind" cmd gets killed (server side) it will stop the foreground monitoring.
> The device will still remain exported if exit at exported state. The user then
> needs to manually unexport the device with "unbind".
> 

My concern is the persistence nature of these exports/imports through
reboots. I have to give it some though on how this can be implemented
addressing my concerns.

>> - What happens when one or more devices are detached?
> 
> If user exit from "attach" cmd running in foreground, followed by detaching the
> device manually, it will work as previously. The device will become available on
> the server for importing again.
> 
> If user running "attach" cmd in foreground, while executing "detach" manually
> from another terminal or similar, the foreground "attach" command will detect
> the disconnection and re-establish the import. I don't see any use case for
> this, it's just for explaining.
> 
> If user running "attach" cmd in foreground, while the remote device becomes
> unexported (or disconnected) it will start polling the usbipd.
> When a device becomes exported on the chosen bus it gets imported immediately.
> 
>> - What happens when one or more devices are unbound from
>>    the server?
>>
>> Let's walk through these scenarios.
> 
> If user exit from "bind" cmd running in foreground, followed by unbind the
> device manually it will work as previous. The usb device will become available
> on the server again.
> 
> If user running "bind" cmd in foreground, while executing "unbind" from another
> terminal or similar, the foreground "bind" command will detect the unexport
> and re-establish the export. I don't see any use case for this, it's just for
> explaining.
> 
> If user running "bind" cmd in foreground, while the device becomes unexported
> or disconnected it will restart monitoring the busid. When a device becomes
> plugged in on the chosen usb port it gets exported immediately.
> 
> One option to consider is to unexport & unimport the device at exit, but this
> comes with the cost of creating a source code dependency between
> bind --> unbind and attach --> detach.
> 

How does this look like in code?

thanks,
-- Shuah

Re: [PATCH v6 0/5] tools/usbip: Patch set summary

[Lars Gunnarsson]

On Tue, Dec 14, 2021 at 03:22:57PM -0700, Shuah Khan wrote:
> On 12/9/21 2:11 PM, Lars Gunnarsson wrote:
> > On Mon, Dec 06, 2021 at 01:02:35PM -0700, Shuah Khan wrote:
> > > On 11/30/21 3:22 PM, Lars Gunnarsson wrote:
> > > > To forward a remote usb device over usbip the following steps is required:
> > > > 
> > > > 1. Execute "usbip bind" on remote end.
> > > > 2. Execute "usbip attach" on local end.
> > > > 
> > > > These steps must be perfomed in above order and after usb device is plugged in.
> > > > If the usb device is unplugged on the remote end the steps above needs to be
> > > > performed again to establish the connection. This patch set implements a feature
> > > > to persistently forward devices on a given bus. When using flag "-p|--persistent"
> > > > on remot end, the USB device becomes exported when plugged in. When using flag
> > > > "-p|--persistent" on local end, the USB device becomes imported when available
> > > > on remote end. Thus it is only required to run the usbip command once on each
> > > > end, in any order, to persistently forward usb devices on a given bus.
> > > > 
> > > > This is sent in five separate patches:
> > > >     tools/usbip: update protocol documentation
> > > >     tools/usbip: update manual pages
> > > >     tools/usbip: add usb event monitor into libusbip
> > > >     tools/usbip: export USB devices on a given bus persistently
> > > >     tools/usbip: import USB devices on a given bus persistently
> > > > 
> > > 
> > > When -p is used, the command stays in foreground. This is a very
> > > different use model compared to current model. In addition, once
> > > persistent flag is set on a bus, all devices even the ones that
> > > are inserted in the future get exported. What happens if one of
> > > the devices shouldn't be exported?
> > 
> > Yes it's conceptually more like exporting/importing the physical usb port,
> > rather than exporting/importing a device plugged into the usb port. Using flag
> > "-p" on both ends will behave like a "virtual" usb hub, a device plugged in on
> > the server (on a chosen bus) will automatically be available on the client.
> > Using flag "-p" has no dependency on the other end though. Using "-p" on one end
> > doesn't enforce usage on the other end. It is only for exporting and importing
> > devices automatically when they become available.
> > 
> > There might be better choices than naming flag to "persistent" for easily
> > communicate this concept. Would "port" be more intuitive?
> > "usbip attach --port 3-3.1" and "usbip bind --port 3-3.1"
> > 
> 
> Terminology isn't what I am concerned about. My concern is the idea of
> automatically making devices available for export at bus level.
> 
> > > 
> > > There are several conditions to be thought through:
> > > 
> > > - What happens if if the command that is running on the foreground
> > >    is killed on either end?
> > 
> > If "attach" cmd gets killed (client side) it will stop the foreground
> > monitoring. The device will still remain imported if user exit at imported state.
> > The user then needs to manually unimport the device with "detach".
> > 
> > If "bind" cmd gets killed (server side) it will stop the foreground monitoring.
> > The device will still remain exported if exit at exported state. The user then
> > needs to manually unexport the device with "unbind".
> > 
> 
> My concern is the persistence nature of these exports/imports through
> reboots. I have to give it some though on how this can be implemented
> addressing my concerns.

Can you elaborate on your thoughts about "the persistence nature of these exports/imports through reboots"?
reboot as in exit from foreground and run the command again?

> 
> > > - What happens when one or more devices are detached?
> > 
> > If user exit from "attach" cmd running in foreground, followed by detaching the
> > device manually, it will work as previously. The device will become available on
> > the server for importing again.
> > 
> > If user running "attach" cmd in foreground, while executing "detach" manually
> > from another terminal or similar, the foreground "attach" command will detect
> > the disconnection and re-establish the import. I don't see any use case for
> > this, it's just for explaining.
> > 
> > If user running "attach" cmd in foreground, while the remote device becomes
> > unexported (or disconnected) it will start polling the usbipd.
> > When a device becomes exported on the chosen bus it gets imported immediately.
> > 
> > > - What happens when one or more devices are unbound from
> > >    the server?
> > > 
> > > Let's walk through these scenarios.
> > 
> > If user exit from "bind" cmd running in foreground, followed by unbind the
> > device manually it will work as previous. The usb device will become available
> > on the server again.
> > 
> > If user running "bind" cmd in foreground, while executing "unbind" from another
> > terminal or similar, the foreground "bind" command will detect the unexport
> > and re-establish the export. I don't see any use case for this, it's just for
> > explaining.
> > 
> > If user running "bind" cmd in foreground, while the device becomes unexported
> > or disconnected it will restart monitoring the busid. When a device becomes
> > plugged in on the chosen usb port it gets exported immediately.
> > 
> > One option to consider is to unexport & unimport the device at exit, but this
> > comes with the cost of creating a source code dependency between
> > bind --> unbind and attach --> detach.
> > 
> 
> How does this look like in code?
> 
> thanks,
> -- Shuah

Re: [PATCH v6 0/5] tools/usbip: Patch set summary

[Shuah Khan]

On 12/16/21 2:01 PM, Lars Gunnarsson wrote:
> On Tue, Dec 14, 2021 at 03:22:57PM -0700, Shuah Khan wrote:
>> On 12/9/21 2:11 PM, Lars Gunnarsson wrote:
>>> On Mon, Dec 06, 2021 at 01:02:35PM -0700, Shuah Khan wrote:
>>>> On 11/30/21 3:22 PM, Lars Gunnarsson wrote:
>>>>> To forward a remote usb device over usbip the following steps is required:
>>>>>
>>>>> 1. Execute "usbip bind" on remote end.
>>>>> 2. Execute "usbip attach" on local end.
>>>>>
>>>>> These steps must be perfomed in above order and after usb device is plugged in.
>>>>> If the usb device is unplugged on the remote end the steps above needs to be
>>>>> performed again to establish the connection. This patch set implements a feature
>>>>> to persistently forward devices on a given bus. When using flag "-p|--persistent"
>>>>> on remot end, the USB device becomes exported when plugged in. When using flag
>>>>> "-p|--persistent" on local end, the USB device becomes imported when available
>>>>> on remote end. Thus it is only required to run the usbip command once on each
>>>>> end, in any order, to persistently forward usb devices on a given bus.
>>>>>
>>>>> This is sent in five separate patches:
>>>>>      tools/usbip: update protocol documentation
>>>>>      tools/usbip: update manual pages
>>>>>      tools/usbip: add usb event monitor into libusbip
>>>>>      tools/usbip: export USB devices on a given bus persistently
>>>>>      tools/usbip: import USB devices on a given bus persistently
>>>>>
>>>>
>>>> When -p is used, the command stays in foreground. This is a very
>>>> different use model compared to current model. In addition, once
>>>> persistent flag is set on a bus, all devices even the ones that
>>>> are inserted in the future get exported. What happens if one of
>>>> the devices shouldn't be exported?
>>>
>>> Yes it's conceptually more like exporting/importing the physical usb port,
>>> rather than exporting/importing a device plugged into the usb port. Using flag
>>> "-p" on both ends will behave like a "virtual" usb hub, a device plugged in on
>>> the server (on a chosen bus) will automatically be available on the client.
>>> Using flag "-p" has no dependency on the other end though. Using "-p" on one end
>>> doesn't enforce usage on the other end. It is only for exporting and importing
>>> devices automatically when they become available.
>>>
>>> There might be better choices than naming flag to "persistent" for easily
>>> communicate this concept. Would "port" be more intuitive?
>>> "usbip attach --port 3-3.1" and "usbip bind --port 3-3.1"
>>>
>>
>> Terminology isn't what I am concerned about. My concern is the idea of
>> automatically making devices available for export at bus level.
>>
>>>>
>>>> There are several conditions to be thought through:
>>>>
>>>> - What happens if if the command that is running on the foreground
>>>>     is killed on either end?
>>>
>>> If "attach" cmd gets killed (client side) it will stop the foreground
>>> monitoring. The device will still remain imported if user exit at imported state.
>>> The user then needs to manually unimport the device with "detach".
>>>
>>> If "bind" cmd gets killed (server side) it will stop the foreground monitoring.
>>> The device will still remain exported if exit at exported state. The user then
>>> needs to manually unexport the device with "unbind".
>>>
>>
>> My concern is the persistence nature of these exports/imports through
>> reboots. I have to give it some though on how this can be implemented
>> addressing my concerns.
> 
> Can you elaborate on your thoughts about "the persistence nature of these exports/imports through reboots"?
> reboot as in exit from foreground and run the command again?
> 

Sorry for the delay in responding.

I have been thinking about this more. I am not convinced that
supporting these use-cases requires usbip changes.

Can we not accomplish the same via scripts/crontab? Monitor if
a bound device is removed and rebind. Do the same on the client
side?

Have you explored if this can be done with existing tools and
a shell script and make use of crontab?

thanks,
-- Shuah