Merge branch 'cbq-fixes'

Vasily Averin says:

====================
cbq: incorrectly low bandwidth blocks limited traffic

v2: patch description changes
Fixes: f0f6ee1f70c4 ("cbq: incorrect processing of high limits")

Mainstream commit f0f6ee1f70c4 ("cbq: incorrect processing of high limits")
have side effect: if cbq bandwidth setting is less than real interface
throughput non-limited traffic can delay limited traffic for a very long time.

This happen because of q->now changes incorrectly in cbq_dequeue():
in described scenario L2T is much greater than real time delay,
and q->now gets an extra boost for each transmitted packet.

Accumulated boost prevents update q->now, and blocked class can wait
very long time until (q->now >= cl->undertime) will be true again.

More detailed problem description can be found here:
http://www.spinics.net/lists/netdev/msg292493.html

Following patches should fix the problem.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>