About the interface-specific systemd services of wpa_supplicant

[Tom Yan]

Hi all!

Just a bit of curiousity on what I mentioned in the title. I see that
the services uses something like:
Alias=multi-user.target.wants/wpa_supplicant-nl80211@%i.service
Alias=multi-user.target.wants/wpa_supplicant@%i.service
Alias=multi-user.target.wants/wpa_supplicant-wired@%i.service

Instead of:
WantedBy=multi-user.target

Was there a particular reason?

Also, all three of them has:
Requires=sys-subsystem-net-devices-%i.device

In that case, instead of:
WantedBy=multi-user.target

Wouldn't it be better to do:
WantedBy=sys-subsystem-net-devices-%i.device

I find that particular useful for USB wireless adapter (which might be
removed from time to time). With that systemd won't be blocked on boot
when it tries to start a wpa_supplicant for a non-existent interface,
and I don't see any adverse effect could be caused as well.

What do you think?