[openib-general] Re: device add/remove in userspace

Sean Hefty mshefty at ichips.intel.com
Wed Oct 26 13:11:34 PDT 2005


Roland Dreier wrote:
>     Sean> Is there a way for a userspace application to know if a
>     Sean> device has been added or removed?
> 
> We don't really handle this right now.  It could probably be made to
> work on top of hotplug/udev/hal/something but it seems tricky to me.

Any idea on how we currently want to handle this?  Can a device remove occur if 
a usermode app is using the device?

The kernel CMA will block until all connection identifiers associated with the 
removed device are freed.  I export the device removal up to userspace through 
the uCMA, but that leaves the kernel blocked until the userspace application 
cleans up.  Doing something more intelligent requires a lot more effort.

- Sean



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