Merge branch 'tc-qevents' into next

Petr Machata  says:

====================

To allow configuring user-defined actions as a result of inner workings of
a qdisc, a concept of qevents was recently introduced to the kernel.
Qevents are attach points for TC blocks, where filters can be put that are
executed as the packet hits well-defined points in the qdisc algorithms.
The attached blocks can be shared, in a manner similar to clsact ingress
and egress blocks, arbitrary classifiers with arbitrary actions can be put
on them, etc.

For example:

 # tc qdisc add dev eth0 root handle 1: \
	red limit 500K avpkt 1K qevent early_drop block 10
 # tc filter add block 10 \
	matchall action mirred egress mirror dev eth1

This patch set introduces the corresponding iproute2 support. Patch #1 adds
the new netlink attribute enumerators. Patch #2 adds a set of helpers to
implement qevents, and #3 adds a generic documentation to tc.8. Patch #4
then adds two new qevents to the RED qdisc: mark and early_drop.

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Signed-off-by: David Ahern <dsahern@kernel.org>