net/sched: cls_api: conditional notification of events

net/sched: cls_api: conditional notification of events

[ Upstream commit 93775590b1ee98bf2976b1f4a1ed24e9ff76170f ]

As of today tc-filter/chain events are unconditionally built and sent to
RTNLGRP_TC. As with the introduction of rtnl_notify_needed we can check
before-hand if they are really needed. This will help to alleviate
system pressure when filters are concurrently added without the rtnl
lock as in tc-flower.

Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Pedro Tammela <pctammela@mojatatu.com>
Link: https://lore.kernel.org/r/20231208192847.714940-8-pctammela@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 369609fc6272 ("tc: Ensure we have enough buffer space when sending filter netlink notifications")
Signed-off-by: Sasha Levin <sashal@kernel.org>