From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH 1/2] net: linkwatch: send change uevent on link changes
Date: Tue, 04 Dec 2018 20:49:59 -0800 (PST)
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From: Jouke Witteveen <j.witteveen@gmail.com>
Date: Sat, 1 Dec 2018 17:00:21 +0100

> Make it easy for userspace to respond to acquisition/loss of carrier.
> The uevent is picked up by udev and, on systems with systemd, the
> device unit of the interface announces a configuration reload.
> 
> Signed-off-by: Jouke Witteveen <j.witteveen@gmail.com>
> ---
> I did not want to change the commit message into a systemd-howto, but
> subscribing to udev events can be done through a line like
>     ReloadPropagatedFrom=sys-subsystem-net-devices-%i.device
> in a systemd unit file.

I want to hear more about "why".

If we have the rtnetlink message that can be listened for, userspace
ought to use that.  That's what it is there for.