"left from <something>" is not correct. "left <something>" would be the
usual form, but "left master interface" is not clear at all. So reword
those messages totally.
Follow-up for 3881fd406b.
The commit 6706ce2fd2 made
IgnoreCarrierLoss= setting also take timespan, to make users handle
issues like #18738 or #20887. But still users needed to explicitly set
a timespan.
This makes networkd automatically determine the timeout when the
situations #18738 or #19832 is detected. Unfortunately, still users have
issue #20887 need to specify a value.
Closes#19832.
Let's raise our supported baseline a bit: CLOCK_BOOTTIME started to work
with timerfd in kernel 3.15 (i.e. back in 2014), let's require support
for it now.
This will raise our baseline only modestly from 3.13 → 3.15.
Previously, even though all Request object are owned by Manager, they
do not have direct reference to Manager, but through Link or NetDev
object. But, as Link or NetDev can be NULL, we need to conditionalize
how to access Manager from Request with the type of the request.
This makes the way simpler, as now Request object has direct reference
to Manager.
This also rename request_drop() -> request_detach(), as in the previous
commit, the reference counter is introduced, so even if a reference of
a Request object from Manager is dropped, the object may still alive.
The naming `request_drop()` sounds the object will freed by the
function. But it may not. And `request_detach()` suggests the object
will not be managed by Manager any more, and I think it is more
appropreate.
This is just a cleanup, and should not change any behavior.
