[RFC PATCH net-next 0/7] DSA master state tracking

This patch set is provided solely for review purposes (therefore not to
be applied anywhere) and for Ansuel to test whether they resolve the
slowdown reported here:
https://patchwork.kernel.org/project/netdevbpf/cover/20211207145942.7444-1-ansuelsmth@gmail.com/

It does conflict with net-next due to other patches that are in my tree,
and which were also posted here and would need to be picked ("Rework DSA
bridge TX forwarding offload API"):
https://patchwork.kernel.org/project/netdevbpf/cover/20211206165758.1553882-1-vladimir.oltean@nxp.com/

Additionally, for Ansuel's work there is also a logical dependency with
this series ("Replace DSA dp->priv with tagger-owned storage"):
https://patchwork.kernel.org/project/netdevbpf/cover/20211208200504.3136642-1-vladimir.oltean@nxp.com/

To get both dependency series, the following commands should be sufficient:
git b4 20211206165758.1553882-1-vladimir.oltean@nxp.com
git b4 20211208200504.3136642-1-vladimir.oltean@nxp.com

where "git b4" is an alias in ~/.gitconfig:
[b4]
	midmask = https://lore.kernel.org/r/%s
[alias]
	b4 = "!f() { b4 am -t -o - $@ | git am -3; }; f"

The patches posted here are mainly to offer a consistent
"master_up"/"master_going_down" chain of events to switches, without
duplicates, and always starting with "master_up" and ending with
"master_going_down". This way, drivers should know when they can perform
Ethernet-based register access.

Vladimir Oltean (7):
  net: dsa: only bring down user ports assigned to a given DSA master
  net: dsa: refactor the NETDEV_GOING_DOWN master tracking into separate
    function
  net: dsa: use dsa_tree_for_each_user_port in
    dsa_tree_master_going_down()
  net: dsa: provide switch operations for tracking the master state
  net: dsa: stop updating master MTU from master.c
  net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}
  net: dsa: replay master state events in
    dsa_tree_{setup,teardown}_master

 include/net/dsa.h  |  8 +++++++
 net/dsa/dsa2.c     | 52 ++++++++++++++++++++++++++++++++++++++++++++--
 net/dsa/dsa_priv.h | 11 ++++++++++
 net/dsa/master.c   | 29 +++-----------------------
 net/dsa/slave.c    | 32 +++++++++++++++-------------
 net/dsa/switch.c   | 29 ++++++++++++++++++++++++++
 6 files changed, 118 insertions(+), 43 deletions(-)

-- 
2.25.1