Merge branch 'net-sched-support-replay-of-filter-offload-when-binding-to-block'

Merge branch 'net-sched-support-replay-of-filter-offload-when-binding-to-block'

Jakub Kicinski says:

====================
net: sched: support replay of filter offload when binding to block

This series from John adds the ability to replay filter offload requests
when new offload callback is being registered on a TC block.  This is most
likely to take place for shared blocks today, when a block which already
has rules is bound to another interface.  Prior to this patch set if any
of the rules were offloaded the block bind would fail.

A new tcf_proto_op is added to generate a filter-specific offload request.
The new 'offload' op is supporting extack from day 0, hence we need to
propagate extack to .ndo_setup_tc TC_BLOCK_BIND/TC_BLOCK_UNBIND and
through tcf_block_cb_register() to tcf_block_playback_offloads().

The immediate use of this patch set is to simplify life of drivers which
require duplicating rules when sharing blocks.  Switch drivers (mlxsw)
can bind ports to rule lists dynamically, NIC drivers generally don't
have that ability and need the rules to be duplicated for each ingress
they match on.  In code terms this means that switch drivers don't
register multiple callbacks for each port.  NIC drivers do, and get a
separate request and hance rule per-port, as if the block was not shared.
The registration fails today, however, if some rules were already present.

As John notes in description of patch 7, drivers which register multiple
callbacks to shared blocks will likely need to flush the rules on block
unbind.  This set makes the core not only replay the the offload add
requests but also offload remove requests when callback is unregistered.

v2:
 - name parameters in patch 2;
 - use unsigned int instead of u32 for in_hw_coun;
 - improve extack message in patch 7.
====================

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