Re: [Xenomai] rtnet issue with xenomai-3.git next branch

[Jeff Webb <jeff.webb@nta-inc.net>]

On 12/17/2014 04:59 AM, Gilles Chanteperdrix wrote:
> On Wed, Dec 17, 2014 at 11:29:10AM +0100, Gilles Chanteperdrix wrote:
>> On Tue, Dec 16, 2014 at 05:29:51PM -0600, Jeff Webb wrote:
>>> I am testing the rtnet functionality in the 'next' branch of xenomai-3.git.  (I now also have Xenomai-2.6.4/rtnet.git running on the same machine for comparison.)  I am able to bring up the real-time interface (rt_e1000e) and use rtping as expected. As mentioned before, I have a primary non-rt ethernet interface running simultaneously (using the e1000e driver).   When I try to remove all the rtnet modules, I am unable to remove rtnet and rtipv4:
>>>
>>> $ rmmod rtipv4 rtnet
>>> rmmod: ERROR: Module rtipv4 is in use
>>> rmmod: ERROR: Module rtnet is in use by: rtipv4
>>>
>>> The messages are the same if I try to remove them individually.  This behavior does not occur with Xenomai-2.6.4/rtnet.git.
>>
>> To avoid nasty side effects, every module which registers an
>> interface (whether rtnet or linux interface) now requires the
>> interface to be down before the module can be removed. The handling
>> of rtnet module counts was significantly reworked when importing
>> into 3.x, it is possible that some bug remains.
>
> Also note that you need this commits in the I-pipe kernel for
> 3.14 for module count to work correctly from xenomai domain:
>
> https://git.xenomai.org/ipipe-gch.git/commit/?h=for-ipipe-3.14.17&id=f009149cf8ca8f956194e4fd852b0d97b7c76886
>

For what its worth, I rebuilt everything using your "for-ipipe-3.14.17" branch that has that commit.  That branch has the same issue, and I think your assessment of the problem is correct.  For instance, this works:

ifconfig eth0 down
ifconfig eth1 down
rmmod e1000e
modprobe rtnet
modprobe rtipv4
modprobe rt_e1000e
rtifconfig rteth1 up 172.18.14.209
rtifconfig
rtifconfig rteth1 down
rmmod rt_e1000e
rmmod rtipv4

But, if I actually use the interface, I can no longer remove the rtipv4 module:

modprobe rtipv4
modprobe rt_e1000e
rtifconfig rteth1 up 172.18.14.209
rtifconfig
rtroute solicit 172.18.14.210 dev rteth1
rtroute
rtifconfig rteth1 down
rmmod rt_e1000e
rmmod rtipv4

-Jeff