[dm-devel] [PATCH 0/9] Generate uevents for all DM events

[Greg KH]

On Mon, Oct 03, 2016 at 12:22:51PM -0700, Andy Grover wrote:
> Hi Mike and GregKH,
> 
> I want a way to get devicemapper events without using the DM ioctl,
> because that requires creating a thread to sleep in the ioctl for each
> dm device I want events from.
> 
> It would seem like using uevents and KOBJ_CHANGE would be a good way
> to do this, but Mike said that the uevent maintainers (Greg that's
> you?) did not think this was a good idea?

KBOJ_CHANGE is a tricky one.  It has been used for a variety of
different things, but usually it is used to show that a major change has
happened with a device like a docking station plug in or out.

How often do DM events happen?  What is triggering them?  How do you
want to send them to userspace?  Through a sysfs file?  Why not just use
your own netlink connection?

thanks,

greg k-h