[openib-general] Re: RFD: uverbs and hotplug

[Roland Dreier]

    Michael> Hello, Roland, all!  How should hotplug work with uverbs?

It's complicated.  Discussion now is useful but I would definitely
prefer to hold off on any implementation until we have the basic
userspace verbs support merged upstream.

One possibility is that it is the administrator's responsibility to
close down all applications using the device before hot-removing it.
Another possibility is as you described: free all the resources
allocated by userspace processes (including remapping any doorbell
pages) before allowing the hot-remove to proceed.  In this case, one
could generate an asynchronous event to tell applications that their
HCA is now gone.

Do you know what happens today if one has a filesystem mounted and then
hot-remove the HBA that is used to get to the underlying block device?

 - R.