From: Stephen Hemminger <stephen@networkplumber.org>
Date: Sat, 27 Dec 2014 09:54:33 -0800

When a netlink event is posted to a socket, the receiving process maybe
waiting to wakeup. Reduce the latency by calling cond_resched() in this
loop. This reduces the problems with missed events during a netlink
storm such as when a routing daemon does mass update in response to
a link transition.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

As mentioned by others, this is potentially invoked from software
interrupts generating netlink events (one example is ipv6) so we
can't try to conditionally sleep here.